! LIBRARY 
UNIVERSITY  OF 
CALIFORNIA 


EARTH 

SCIENCES 

LIBRARY 


PLATE  1.     Frontispiece 


CHARACTERISTICS 


OF 


EXISTING   GLACIERS 


, 

WILLIAM  HERBERT   HOBBS 

// 

PROFESSOR   OF   GEOLOGY   IN   THE    UNIVERSITY   OF    MICHIGAN 


"  The  present  is  the  key  to  the  past."  —  SIR  CHARLES  LYELL 


!Nefo  gorfe 

THE  MACMILLAN  COMPANY 
1911 

All  rights  reserved 


COPYRIGHT,  1911, 
BY  THE  MACMILLAN  COMPANY. 

Set  up  and  electrotyped.     Published  May,  191 1. 


J.  S.  Gushing  Co.  —  Berwick  &  Smith  Co. 
Norwood,  Mass.,  U.S.A. 


EARTH 

SCIENCES 

LIBRARY 


Co 

PROFESSOR  VICTOR  GOLDSCHMIDT 

OF    THE 

UNIVERSITY   OF    HEIDELBERG 

A    LEADER    IN    SCIENTIFIC    RESEARCH 

A    GIFTED    AND     INSPIRING     TEACHER 

AND  A  NOBLE  AND  GENEROUS  FRIEND 

THIS    BOOK    IS   AFFECTIONATELY    DEDICATED 

BY 

THE   AUTHOR 


334627 


PREFACE 

IT  has  been  the  common  practice  to  treat  the  subject 
of  glaciation  as  if  all  ice  masses  having  inherent  motion 
of  whatever  nature  were  governed  by  the  same  laws. 
Thus  the  most  recent  and  authoritative  work  upon  the 
subject  has  treated  the  glaciers  of  Greenland  and  Switzer- 
land together.  The  aim  of  the  present  w^ork  has  been 
rather  to  emphasize  the  wide  differences  in  other  than 
dimensional  respects  which  separate  such  bodies,  and 
to  show  that  the  laws  which  govern  their  nourishment 
and  depletion,  and  their  reaction  with  the  lithosphere  as 
well,  are  by  no  means  identical. 

The  broad  line  of  cleavage  is  found  to  lie  between  those 
glaciers  which  completely  cover  a  considerable  portion 
of  the  rock  surface,  and  have  the  form  of  a  flat  dome  or 
shield,  and  the  remaining  types.  These  latter  glaciers 
being  all  restricted  to  mountain  districts  have  been  desig- 
nated mountain  glaciers,  and  they  have  been  found  to 
bear  very  simple  relations  to  each  other,  dependent  upon 
the  measure  of  their  nourishment  and  waste.  Alimenta- 
tion being  in  turn  dependent  upon  climatic  conditions, 
all  are  brought  in  order  within  the  cycle  of  changes 
which  correspond  to  a  period  of  increasingly  rigorous 
climate  followed  in  turn  by  more  genial  conditions  —  the 
cycle  of  glaciation.  Throughout  the  attempt  has  been 
to  emphasize  the  broader  physiographic  elements  of  the 
problem  and  to  show  the  relations  to  alimentation  and 
depletion. 

vii 


viii  PREFACE 

No  attempt  has  here  been  made  to  set  forth  the  views 
of  that  school  of  British  geologists  particularly  which 
holds  that  the  denudational  effect  of  glacier  ice  is  nega- 
tive, because  it  protects  the  basement  from  the  process 
of  weathering.  As  will  appear  from  the  text,  the  writer 
believes  that  protection  from  weathering  on  the  cirque 
floor  combined  with  effective  wreathering  at  the  base  of 
the  cirque  wall,  explains  the  lateral  migration  of  the 
glacial  amphitheatre.  The  doctrine  of  protection  by  ice 
has  been  given  so  recent  an  exposition  by  an  eminent 
prophet  of  this  school  with  the  expressed  approval  of  his 
colleagues,  that  it  is  believed  more  is  gained  from  setting 
forth  the  evidence  from  one's  own  viewpoint  than  by 
entering  into  controversy.  Even  the  names  "glacial 
protection  "  and  "  glacial  erosion  "  as  applied  to  the  two 
schools  to-day  seem  inappropriate. 

The  materials  of  this  volume  are  three  papers  which 
have  been  published  at  London,  Philadelphia,  and  Berlin 
during  the  year  1910.  The  first  of  the  series  appeared 
in  the  Geographical  Journal  under  the  title  "  The  Cycle 
of  Mountain  Glaciation."  In  a  greatly  expanded  form 
it  is  Part  I  of  the  present  volume.  The  remaining  parts, 
though  originally  published  in  technical  journals,  were 
written  with  a  view  to  their  republication  in  book  form, 
and  have  in  consequence  been  less  altered.  Of  these  the 
earlier  appeared  in  the  Proceedings  of  the  American  Philo- 
sophical Society  under  the  title,  "  Characteristics  of  the 
Inland-ice  of  the  Arctic  Regions"  ;  while  the  concluding 
part  was  published  a  few  months  later  at  Berlin  in  the 
international  journal  of  glaciology  bearing  the  title,  "  The 
Ice  Masses  on  and  about  the  Antarctic  Continent."  To 
the  Royal  Geographical  Society  of  London,  the  American 
Philosophical  Society  of  Philadelphia,  and  the  editor  of 
the  Zeitschrift  fur  Gletscherkunde,  the  author  is  under 


PREFACE  ix 

obligation  for  permission  to  republish  the  papers  in  their 
present  form.  Although  they  contain  original  material 
and  of  necessity  make  use  of  technical  terms,  it  is  thought 
that  the  language  will  in  the  main  be  intelligible  to  the 
general  reader  as  well  as  to  the  specialist  in  glaciology. 

ANN  ARBOR,  MICHIGAN, 

November  2,  1910. 


CONTENTS 

INTRODUCTION 

PAGK 

The  ancestry  of  glacial  theories  —  The  factor  of  air  temperature  — 
Mountain  versus  continental  glaciers  —  Low  level  versus  high  level 
sculpture  —  References .  1 

PART   I 
MOUNTAIN  GLACIERS 

CHAPTER  I 
THE  CIRQUE  AND  ITS  RECESSION 

The  glacial  amphitheatre  in  literature  —  Relation  of  cirque  to  berg- 

schrund  —  The  schrundline  —  Initiation  of  the  cirque,  nivation 

References 12 

CHAPTER  II 
HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND 

The  upland  dissected — Modification  in  the  plan  of  the  cirque  as 
maturity  is  approached  —  Grooved  and  fretted  uplands  —  Charac- 
teristic high  relief  forms  of  the  fretted  upland  — The  col  and  its 
significance  —  The  advancing  hemicycle  —  References  ...  25 

CHAPTER  III 

CLASSIFICATION  OF  GLACIERS  BASED  UPON  COMPARATIVE 
ALIMENTATION 

Relation  of  glacier  to  its  bed  —  Ice-cap  type  —  Piedmont  type  — 
Transection  type  —  Expanded-f  oot  type  —  Dendritic  or  valley  type 
—  Inherited  basin  type  —  Tide-water  type  —  Radiating  (Alpine) 

type  —  Horseshoe  type  —  References 41 

xi 


xii  CONTENTS 

CHAPTER  IV 
Low  LEVEL  GLACIAL  SCULPTURE  IN  MODERATE  LATITUDES 

PAGB 

The  cascade  stairway  —  Mechanics  of  the  process  which  produces  the 
cascade  stairway — The  U-shaped  glacier  valley — The  hanging 
side  valley  —  References  .........  59 

CHAPTER  V 
HIGH  LATITUDE  GLACIAL  SCULPTURE 

Variations  in  glacial  sculpture  dependent  upon  latitude  —  Surface 
features  of  Northern  Lapland  —  The  flatly  grooved  valleys  and 
the  scattered  knobs — The  fjords  of  Western  Norway  —  The  rock 
pedestals  bounded  by  fjords  —  The  Norwegian  find  —  References  .  70 

CHAPTER  VI 
GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION 

Abandoned  moraines  of  mountain  glaciers  —  The  tongue-like  basin 
before  the  mountain  front  —  Border  lakes  —  Stream  action  on  the 
mountain  foreland  —  The  outwash  apron  —  Eskers  and  recessional 
moraines  —  Stream  action  within  the  valley  during  retirement  of 
the  glacier  —  Landslides  and  rock  streams  within  the  vacated 
valley — Rock  flows  from  abandoned  cirques  —  References  .  .  81 

PART   II 

ARCTIC   GLACIERS 

CHAPTER  VII 
THE  ARCTIC  GLACIER  TYPE 

Introduction  —  North  and  south  polar  areas  contrasted  —  The  fixed 
areas  of  atmospheric  depression  —  Ice-caps  of  Norway  —  Ice-caps 
of  Iceland — Ice-covered  archipelago  of  Franz  Josef  Land  —  The 
smaller  areas  of  inland-ice  within  the  Arctic  regions  —  The  inland- 
ice  of  Spitzbergen  —  The  inland-ice  of  Grinnell,  Ellesmere,  and 
Baffin  lands  —  References 97 

CHAPTER  VIII 
PHYSIOGRAPHY  OF  THE  CONTINENTAL  GLACIER  OF  GREENLAND 

General  form  and  outlines  —  The  ice  face  or  front  —  Features  within 
the  marginal  zone  —  Dimples  or  basins  of  exudation  above  the 


CONTENTS  xiii 

PAGE 

marginal  tongues — Scape  colks  and  surface  moraines  —  Marginal 
moraines — Fluvio-glacial  deposits  —  References     ....    119 

CHAPTER  IX 
NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE 

Few  and  inexact  data  —  Snowfall  in  the  interior  of  Greenland  —  The 
circulation  of  air  over  the  isblink — Foehn  winds  within  the  coastal 
belt  —  Wind  transportation  of  snow  over  the  desert  of  inland-ice 
—  Fringing  glaciers  formed  from  wind  drift  —  Nature  of  the  sur- 
face snow  of  the  inland-ice  —  Snowdrift  forms  of  deposition  and 
erosion,  sastrugi  —  Source  of  the  snow  in  cirrus  clouds  —  Refer- 
ences    .  .  143 

CHAPTER  X 
DEPLETION  OF  THE  GREENLAND  ICE  FROM  SURFACE  MELTING 

Eastern  and  western  slopes  compared  —  Effect  of  the  warm  season 
within  the  marginal  zones  of  the  inland-ice  —  Differential  surface 
melting  of  the  ice  —  Moats  between  rock  and  ice  masses  —  Engla- 
cial  and  subglacial  drainage  of  the  inland-ice  —  The  marginal 
lakes  —  Ice  dams  in  extraglacial  drainage  —  Submarine  wells  in 
fjord  heads  —  References 1(52 

CHAPTER  XI 
DISCHARGE  OF  BERGS  FROM  THE  ICE  FRONT 

The  ice  cliff  at  fjord  heads  —  Manner  of  birth  of  bergs  from  studies  in 
Alaska — Studies  of  bergs  born  of  the  inland-ice  of  Greenland — 
References  178 


PART  III 
ANTARCTIC   GLACIERS 

CHAPTER  XII 
THE  ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE 

General  uniformity  of  conditions  in  contrast  with  the  north  polar 
region  —  Antarctic  temperatures — Geographical  results  of  ex- 
ploration—  The  submerged  continental  platform  —  The  zone  of 
sea  and  pack  ice  —  The  ice  islands  and  ice-foot  glaciers  —  Refer- 
ences 186 


xiv  CONTENTS 

CHAPTER  XIII 
THE  MARGINAL  SHELF  ICE 

PAGE 

Its  nature  and  distribution  —  The  "  Great  Ross  Barrier,"  Victoria  Land 

—  The  "  higher  "  and  "  lower  "  ice  terraces  off  King  Oscar  Land  — 
The  u  west-ice  "  of  Kaiser  Wilhelrn  Land  —  The  ice  barrier  tongues 
of  Victoria  Land  —  The  rectangular  table  berg  of  Antarctic  waters 

—  References 214 

CHAPTER  XIV 
THE  ANTARCTIC  CONTINENTAL  GLACIER  WHERE  UNCONFINED 

The  inland-ice  margin  on  Kaiser  Wilhelm  Land  —  The  blue  icebergs 

of  Antarctica  —  Origin  of  the  West-ice  —  References     .        .        .    245 

CHAPTER  XV 

THE  ANTARCTIC  CONTINENTAL  GLACIER  WHERE  BEHIND  A 
MOUNTAIN  RAMPART 

The  inland-ice  of  Victoria  Land  —  Marginal  sections  along  the  outlets 

—  Dimples  of  the  ice  surface  above  the  outlets  —  Ice  aprons  below 
outlets  —  Moats  surrounding  rock  masses  —  Mountain  glaciers  on 
outer  slope  of  the  retaining  ranges  —  Ice  slabs  —  References          .     253 

CHAPTER   XVI 

THE  NOURISHMENT  OF  ANTARCTIC  ICE  MASSES 

The  Greenland  ice  in  its  relation  to  the  Antarctic  continental  glacier  — 

Air  temperatures,  humidity,  and  isolation  —  Nature  of  the  snow 

•    precipitated  in  Antarctica  —  Winds  upon  the  continental  margins 

—  The  Antarctic  continental  (glacial)  anticyclone  —  Wind  direc- 
tion determined  by  snow-ice  slope  —  The  southerly  f oehn-blizzard 
of  the  ice  plateau  —  Wind  transportation  of  snow  —  High  level 
cirrus  clouds  the  source  of  the  snow  in  the  interior  of  Antarctica 

—  Former  extent  of  Antarctic  glaciation  —  References.        .        .     261 

AFTERWORD 

The  two  contrasted  glacier  types  —  Physiographic  form  —  Denuding 

processes  —  Alimentation  —  Marginal  contours       ....    285 


LIST   OF   PLATES 


1.  The  Bishops  Glacier  in  the  Bishops  Range  of  the  Selkirks,  with 

the  Purity  Range  beyond Frontispiece 

FACING    PAGE 

2.  A.    Summer  snow  bank  surrounded  by  a  brown  border  of  finely 

comminuted  rock,  Quadrant  Mountain,  Y.  N.  P.   .         .         .      20 
B.   Snow  bank  lying  in  a  depression  largely  of  its  own  construc- 
tion, Quadrant  Mountain,  Y.  N.  P. 

3.  A.   View  of  the  Yoho  Glacier  at  the  head  of  the  Yoho  Valley, 

Canadian  Rockies 26 

B.  Pre-glacial  upland  on  Quadrant  Mountain,  invaded  by  the 
cirque  known  as  the  "  Pocket " 

4.  Maps  to  illustrate  progressive  dissection  of  an  upland    ...       28 

i.  Early  stage  of  glaciation  2.  Further  investment  of  the 
upland  to  produce  a  grooved  upland.  3.  Early  maturity. 
4.  Complete  dissection  at  maturity  producing  a  fretted  upland. 

5.  Multiple  secondary  cirques  on  the  west  face  of  the  Wannehorn  seen 

across  the  Great  Aletsch  Glacier  .......       28 

6.  A.   a.  A  grooved  upland  in  the  Bighorn  Mountains,  Wyoming; 

b.  A  fretted  upland,  Alaska 30 

B.  Multiple  cirque  of  the  Dawson  Glacier  seen  from  the  Asulkan 
Pass,  Selkirks 

7.  A.   Fretted  upland  of  the  Alps  as  seen  from  the  summit  of  Mont 

Blanc 30 

B.  Map  of  a  portion  of  one  of  the  Lofoten  Islands,  showing  a 
fretted  surface  in  part  submerged  and  emphasizing  the 
approximate  accordance  of  summit  levels 

8.  A  karling  in  North  Wales 32 

9.  A.   The  Matterhorn  from  the  Gorner  Grat,  near  the  Riffelhorn     .      34 
B.   Col  of  the  Overlook  looking  across  the  foot  of  the  Illecillewaet 

Glacier,  Selkirks 

10.  A.   Expanded  forefoot  of  the  Foster  Glacier,  Alaska       ...      44 
B.   Type  of  piedmont  glacier 

11.  Types  of  mountain  glaciers       ........      48 

12.  A  hanging  glacieret,  the  Triest  Glacier  above  the  Great  Aletsch 

Glacier  of  Switzerland  .  50 

13.  A.   A  hanging  tributary  valley  meeting  a  trunk  glacier  valley 

above  the  present  water  level  on  the  "  inside  passage  "  to 

Alaska .        .        .52 

B.   Irregularly  bounded  n£ves  upon  the  volcanic  cone  of  Mt.  Ranier 


xvi  LIST  OF  PLATES 

PLATE  FACING  PAGK 

14.  A.   Series  of  hanging  glacierets  which  extend  the  Asulkan  Glacier 

in  the  Selkirks 54 

B.  View  of  the  Wenkchemna  Glacier  in  the  Canadian  Rockies 

15.  Surface  moulded  by  mountain  glaciers  near  the  ancient  Lake  Mono 

in  the  Sierra  Nevadas  of  California 60 

16.  A.   The  Little  Cottonwood  Canyon  in  the  Wasatch  Range  trans- 

formed at  the  bottom  into  the  characteristic  U -section          .       64 
B.   Striated  surface  of  glaciated  valley  floor  near  Loch  Coriusk, 
Skye 

17.  A.   The  Hardangerjb'kull  and  the  Kongsnut  nunatak      ...      76 
B.   Upland  glaciated   by   mountain   glaciers  and    partially  sub- 
merged through  depression 

18.  A.   Development  of  tinds  on  the  margin  of  the  Jostedalsbraen       .      78 
B.   Typical  tinds  on  the  margin  of  a  fjord 

19.  A.   Rock  stream  in  a  cirque  of  Greenhalgh  Mountain,  Silverton 

quadrangle,  Colorado 96 

B.   Rock  stream  at  head  of  a  cirque,  in  the  silver  basin,  Silver- 
ton  quadrangle,  Colorado 

20.  Map  of  a  portion  of  the  Jostedalsbraen    ......     102 

21.  Map  of  the  margin  of  an  Icelandic  ice-cap 104 

22.  A.   Fretted  upland  carved  by  mountain  glaciers  about  King  Oscar's 

Fjord,  Eastern  Greenland 124 

B.   Front  of  the  Bryant  glacier  tongue,  showing  the  vertical  wall 
and  the  stratification  of  the  ice 

23.  A.   Portion  of  the  southeast  face  of  the  Tuktoo  glacier  tongue, 

showing  the  projection  of  the  upper  layers  apparently  as  a 

result  of  overthrust 128 

B.   Ice  face  at  eastern  margin  of  the  inland-ice  of  Greenland  in 
latitude  77°  30'  N. 

24.  A.   Normal  slope  of  the  inland-ice  at  the  land  margin  near  the 

Cornell  tongue 130 

B.   Hummocky  moraine  on  the  margin  of  the   Cornell   glacier 
tongue 

25.  A.  Lateral  glacial  stream  flowing  between  ice  and  rock,  Benedict 

glacier  tongue,  Greenland      .......     170 

B.   The  ice-dammed  Lake  Argentine  in  Patagonia 

26.  A.   Ice-dammed  lakes  on  the  margin  of  the  Cornell  tongue  of  the 

inland-ice        ..........     174 

B.   Delta  in  one  of  the  marginal  lakes  of  the  Cornell  glacier 
tongue 

27.  A.   The  fringing  glaciers  about  Sturge  Island,  Balleny  Group        .     208 
B.   An  ice-foot,  with  boat  party  landing 

28.  A.   The  ice-sheathed  Bouvet  Island,  latitude  54°  26'  S.,  longitude 

3°  24'  E.  (after  Chun) 208 

B.   Neve  stratification  in  ice  island  (after  Arctowski) 


LIST  OF  PLATES  Xvii 

PLATE  FACING  PAGE 

29.  A.  The  margin  of  the  Great  Ross  Barrier 216 

B.   Near  view  of  the  Great  Ross  Barrier  where  highest —  280  feet 

30.  A.   Surface  of  the  great  shelf  ice  to  the  south  of  Minna  Bluff         .     220 
B.   Surface  of  the  great  shelf  ice  viewed  from  a  balloon  and  show- 
ing sastrugi 

31.  A.   A  new  ice-face  on  the  Great  Barrier  ......     222 

B.   An  old  ice-face  on  the  Great  Barrier 

32.  View  of  the  inland-ice  of  Kaiser  Wilhelm  Land  from  the  top  of 

the  Gaussberg 246 

33.  A.   View  of  the  Gaussberg  surrounded  by  inland-ice  in  a  depressed 

zone 258 

B.   Moat  surrounding  rock  which  projects  from  the  ice  surface 

34.  A.   View  of  the  high  surfaces  of  the  Jotemheim  from  the  Galdha, 

Norway  (after  Fritz  Machacek) 286 

B.  The  Maelkevoldsbrae  of  the  Jostef  jeld,  showing  the  develop- 
ment of  tinds  about  the  borders  of  a  Norwegian  plateau 
glacier  (after  Fritz  Machacek) 


ILLUSTRATIONS   IN   THE   TEXT 


FIG. 


1.  Ideal  section  across  inland-ice  ........  7 

2.  Section  across  a  mountain  upland  occupied  by  glaciers  ...  7 

3.  View/of  the  ice-cap  of  the  Eyriksjokull,  Iceland      ....  7 

4.  A  glacial  cirque  excavated  from  the  Pleistocene  glaciated  surface 

of  Norway      .         .         .         .         .         .         .         .  .         .14 

5.  Bergschruud  below  cirque  wall  on  a  glacier  of  the  Sierra  Neyadas, 

California       ...........  16 

6.  Schrundline  near  Mt.  McClure,  Sierra  Nevadas  of  California          .  18 

7.  Cross-section  of  a  steep  snowdrift  site,  showing  recession  by  niva- 

tion         ............  19 

8.  Characteristic  form  of  drift  sites  on  hillsides  in  Swedish  Lapland  .  21 

9.  Pre-glacial  upland  invaded   by  cirques,  "  biscuit  cutting  "  effect, 

Bighorn  Mountains        .........  26 

10.  View  of  the  scalloped  tableland  within  the  Uinta  Range         .         .  27 

11.  Map  of  Quadrant  Mountain,  a  remnant  of  the  pre-glacial  upland 

on  the  flanks  of  the  Gallatin  Range,  Y.  N.  P  .....  27 

12.  Series  of  semicircular  glacial  amphitheatres  whose  scalloped  crest 

forms  part  of  the  divide  of  the  North  American  continent           .  28 

13.  Diagram  to  illustrate  the  manner  of  dissection  of  an  upland  by 

mountain  glaciers  .         .         .         .         .         .         .  .         .31 

14.  Position  of  the  Aletschhorn  and  Dreieckhorn  between  the  Upper, 

Middle,  and  Great  Aletsch  neves  .......  33 

15.  Illustration  of  the  formation  of  cols  through  the  intersection  of 

cirques  ............  34 

16.  Map  of  a  transection  glacier     ........  45 

17.  The  Baird  glacier,  a  typical  expanded-foot  glacier  .         .         .46 

18.  Outline  map  of  the  Hi  spar  glacier,  Himalayas         .         .         .         .47 

19.  Outline  map  of  the  Tasman  glacier,  New  Zealand  .         .  48 

20.  Outline  map  of  an  inherited  basin  glacier        .....  49 

21.  Outline  map  of  a  reconstructed  glacier    ......  50 

22.  Outline  plan  of  a  radiating  glacier  .......  53 

23.  Outline  map  of  the  Asulkan  Glacier  in  the  Selkirks        ...  54 

24.  Outline  map  of  the  Wenkchemna  Glacier  in  the  Canadian  Rockies  55 

25.  Longitudinal  section  along  a  glaciated  mountain  valley,  showing 

reverse  grades  and  rock  basin  lakes  in  series        ....  60 

26.  Rock  bar  with  basin  showing  above          ......  62 

27.  Ideal  cross-section  of  a  U-shaped  valley  once  occupied  by  a  moun- 

tain glacier    .        .        .        .        .        .        .        .        .        .        .64 

xix 


XX  ILLUSTRATIONS   IN   THE  TEXT 


FIG. 


28.  View  in  the  glaciated  Sierra  Nevadas  of  California,  showing  the 

sharp  line  which  sometimes  separates  the  zone  of  erosion  from 
that  of  sapping 65 

29.  Normal  valleys  from  sub-aerial  erosion 66 

30.  Glaciated  and  non-glaciated  valleys  tributary  to  a  glaciated  main 

valley  —  hanging  valleys       .        •        •        .        ...         .07 

31.  Comparison  of  the  longitudinal  profile  of  a  mature  stream-cut 

valley  and  its  tributaries  with  a  glacier-carved  Alpine  valley 
and  its  tributaries          .       .,         .         t        .        v:      .         .         .       68 

32.  Surface  in  Swedish  Lapland  moulded  by  continental  glaciers  and 

subsequently  grooved  by  sluggish  mountain  glaciers  ...       71 

33.  Map   of  area  in   Swedish   Lapland,   showing  cirques    and    kar- 

lings       .         .        .        .        .        ...        .  ;        «       72 

34.  Map  of  area  in  Swedish  Lapland  moulded  by  sluggish  glaciers 

which  succeeded  continental  glaciation        .        .        .        .        .      73 

35.  Characteristic  features  due  to  glacial  sculpture  in  Scandinavia       .       74 

36.  Map  of  the  vicinity  of  the  Storf  jord,  showing  the  regular  arrange- 

ment of  fjords  and  submerged  valleys .        .        .        .  75 

36  a.   Nunataks  rising  out  of  the  surface  of  a  Norwegian  ice-cap  near 

its  margin    .         .         .        .        »        .        .        .  .        .76 

37.  Erosional  surface  due  to  ice-cap  glaciation  within  the  marginal 

zone        .         .         .         .         .         .        .        ......      76 

38.  The  Seven  Sisters,  sharpened  ice-cap  nunataks  in  Northwestern 

Norway  due  to  overflow  of  glacier  streams  at  margins        /.        .       77 

39.  Broad  glacial  trough  overdeepened  through  uplift  and  subsequent 

glaciation «        ....        .        .77 

40.  Circular  tind  with  acute  apex  from  the  Lofoten  Islands          .         .       78 

41.  Successive  diagrams  to  illustrate  a  theory  of  the  shaping  of  acute 

circular  tinds  through  exfoliation 79 

42.  Terminal  and  lateral  moraines  remaining  from  earlier  mountain 

glaciers  .         .         .        .        .       *.        .         .        .         •         •         .81 

43.  Sketch  map  of  the  morainic  ridges  near  the  mouth  of  Little  Cot- 

tonwood  Canyon  in  the  Wasatch  Range 82 

44.  Convict  Lake,  a  lake  behind  a  morainal  dam  in  a  glaciated  valley 

of  the  Sierra  Nevadas  of  California 82 

45.  Map  of  the  moraines  and  drurnlins  within  and  about  the  apron  of 

the  piedmont  glacier  of  the  Upper  Rhine     .         .        .        .        .       83 

46.  Lake  Garda  in  the  southern  gateway  to  the  Alpine  highland  on 

the  apron  site  of  the  earlier  piedmont  glacier       .         .        ...       84 

47.  Outline  map  of  the  northern  border  of  the  Alps,  showing  the 

basins  of  former  lakes 85 

48.  A  braided  stream  flowing  from  the  margin  of  a  glacier  ...       86 

49.  Ideal  form  of  tongue-like  basin  remaining  on  the  site  of  the  apron 

of  a  piedmont  glacier 88 

50.  Gorge  of  the  Albula  river  near  Berkun  in  the  Engadine         .        .       90 


ILLUSTRATIONS  IN  THE  TEXT  xxi 


FTG. 


51.  Ideal  section  showing  successive  slides  from  a  canyon  wall  so  as 

to  produce  a  staircase  effect  ........       92 

52.  View  of  the  succession  of  rock  slides  from  the  north  rock  wall  of 

the  Upper  Rhine  near  the  town  of  Flims     .....      93 

53.  Map  of  two  high  glacial  cirques  now  partially  occupied  by  rock 

streams  ............       95 

54.  Map  showing  the  areas  of  fixed  low  barometric  pressure  and  of 

heavy  glaciation  in  the  Northern  Hemisphere     ....     100 

55.  Idealized  section  showing  the  form  of  "fjeld"  and  "brae"  in 

Norwegian  ice-cap          .........     101 

56.  Maps  of  the  Hofs  Jokull  and  the  Lang  Jokull         .         .        .         .102 

57.  Map  of  the  Vatna  Jokull  .........     103 

58.  Cross-section  of  the  Vatna  Jokull  from  north  to  south    .         .         .     104 

59.  Map  of  the  ice-capped  islands  in  the  eastern  part  of  the  Franz 

Josef  Archipelago          .........     107 

60.  Typical  ice  cliff  of  the  coast  of  Prince  Rudolph  Island,  Franz  Josef 

Land      ............     108 

61.  Map  of  Nova  Zembla,  showing  the   supposed  area  covered   by 

inland-ice       ...........     109 

62.  Map  of  Spitzbergen,  showing  the  supposed  glacier  areas         .         .110 

63.  Inland-ice  of  New  Friesland  as  viewed  from  Hinloopen  Strait        .     Ill 

64.  Map  of  the  southwestern  margin  of  an  extension  of  the  inland- 

ice  of  New  Friesland     .........     112 

65.  Camping  place  in  one  of  the  "canals"  upon  the  surface  of  the 

inland-ice  of  North  East  Land      .......     114 

66.  Hypothetical  cross-section  of  a  glacial  canal  upon  the  inland-ice 

of  North  East  Land      .........     115 

67.  Map  showing  the  supposed  area  of  inland-ice  upon  Grinnell  and 

Ellesmere  Lands    ...  .....     115 

68.  View  of  the  "Chinese  Wall"  on  Grinnell  Land       .         .         .         .116 

69.  Map  showing  the  supposed  area  of  inland-ice  upon  Baffin  Land      .     11? 

70.  Map  of  Greenland,  showing  the  outlines  of  the  inland-ice  and  the 

routes  of  explorers  .         .         .         .         .         .         .        .120 

71.  Route   of  Garde  across  the  margin  of  the  inland-ice  of   South 

Greenland      ...........     121 

72.  Sketch  of  the  east  coast  of  Greenland,  showing  the  inland-ice  and 

the  work  of  marginal  mountain  glaciers      .....     122 

73.  Section  across  the  inland-ice  of  Greenland  near  the  64th  parallel 

of  latitude      ...........     122 

74.  Comparison  of  the  several  profiles  across  the  margin  of  the  inland- 

ice  of  Greenland    .  .......     123 

75.  Map  of  the  region  about  King  Oscar's  and  Kaiser  Franz  Josef 

Fjords,  eastern  Greenland     ........     124 

76.  Map  of  a  glacier  tongue  which  extends  from  the   inland-dee  of 

Greenland  down  the  Umanak  Fjord  ....     125 


xxii  ILLUSTRATIONS  IN  THE  TEXT 

FIG.  PAGE 

77.  Tongues  of  ice  which  descend  from  the  Foetal  glacier  .         .         .     126 

78.  Map  of  the  Greenland  shore  in  the  vicinity  of  the  Northeast 

Foreland 127 

79.  A  series  of  parallel  crevasses  on  the  inland-ice  of  South  Green- 

land       129 

80.  Rectangular  network  of  crevasses  on  the  surface  of  the  inland- 

ice  of  South  Greenland 130 

81.  Map  showing  routes  of  sledge  journeys  in  North  Greenland          .     133 

82.  a.  Closure  of  the  Neu-Haufen  Dyke,  Schiittau ;    b.  Scape  colks 

near  Dalager's  Nunataks     ........     136 

83.  Diagram  to  show  the  effect  of  a  basal  obstruction  in  the  path  of 

the  ice  near  its  margin 139 

84.  Surface  marginal  moraines  of  the  inland-ice  of  Greenland    .         .     139 

85.  Diagram  to  illustrate   the  air  circulation  over  the   isblink   of 

Greenland    ...........  147 

86.  On  the  Sahara  of  snow    .........  151 

87.  Sastrugi  on  the  inland-ice  of  North  Greenland       ....  155 

88.  Barchans  in  snow 156 

89.  Diagrams  showing  the  distribution  of  temperatures  within  the 

surface  zones  of  the  inland-ice    .         .         .         .         .         .         .164 

90.  Map  showing  the  superglacial  streams  within  the  marginal  zone 

of  the  inland-ice 165 

91.  Diagrams  to  show  the  effects  on  differential  melting  on  the  ice 

surface '.  166 

92.  Fragments  of  rock  of  different  sizes  to  show  their  effect  upon 

melting         ...........     167 

93.  Section  showing  the  so-called  "  cryoconite  holes  "  upon  the  surface 

of  an  ice  hummock 168 

94.  Map  showing  the  margin  of  the  Frederikshaab  ice  apron  extend- 

ing from  the  inland-ice  of  Greenland,  and  showing  the  position 

of  ice-dammed  marginal  lakes     .......     171 

95.  Diagram  showing  arrangement  of  shore  lines  from  marginal  lakes 

to  the  northward  of  the  Frederikshaab  ice  tongue  if  its  front 
should  be  retired          .........     172 

96.  Sections  from  the  inland-ice  through  the  Great  and  Little  Kara- 

jak  tongues  to  the  Karajak  Fjord 179 

97.  Origin  of  bergs  as  a  result  especially  of  wave  erosion    .         .         .180 

98.  Supposed  successive  forms  of  a  tide-water  glacier  front         .         .181 

99.  Large  berg  floating  in  Melville  Bay  and  surrounded  by  sea-ice     .     182 

100.  Map  of  Antarctica,  showing  the  principal  points  which  have  been 

reached  by  exploring  expeditions .194 

101.  Map  of  the  Antarctic  region,  giving  the  tracks  of  vessels  and 

the  margins  of  the  continent       , 195 

102.  Soundings  over  the  continental  platform  to  the  westward  of  West 

Antarctica   .        .        .        ...        «       v       •        •        •     197 


ILLUSTRATIONS  IN  THE  TEXT  xxiii 


r  &wi 

103.  Cracks  formed  on  the  free  surface  of  an  elastic  block  when  crushed 

in  a  testing  machine 201 

104.  Open  lane  of  water  within  the  Antarctic  pack-ice,  showing  the 

minor  elements  of  similar  form  which  by  separating  yield 

*  •  909 

zigzag  margins     .....•••••     ^u^ 

105.  Lozenge-shaped   lakes  within   the  Antarctic  pack  arranged  en 

echelon  .......••••     20- 

106.  Sastrugi  on  pack-ice  off  Kaiser  Wilhelm  Land  as  seen  from  a 

balloon 204 

107.  Pressure  lines  upon  the  surface  of  sea-ice 204 

108.  Pressure  ridge  formed  on  the  shore  of  Victoria  Land    .         .         .  205 

109.  The  Antarctica  sinking  after  being  crushed  in  the  pack         .         .  205 

110.  Domed  ice  island  off  King  Edward  Land       .         .         .    .     .         .  209 

111.  King  Edward  Land  with  ice  shelf  in  front 215 

112.  View  of  the  shelf-ice  of  Coats  Land 216 

113.  Map  of  the  Ross  Barrier  edge 217 

114.  Section  along  the  Ross  Barrier  edge,  showing  submerged  portion 

and  the  underlying  water  layer 217 

115.  a.  Low  margin  of   Ross  Barrier  on  Balloon  Inlet ;  b.  Relatively 

high  margin  of  the  Barrier  on  Balloon  Inlet      ....  219 

116.  Outline  map  of  the  known  portions  of  the  Great  Ross  Barrier      .  220 

117.  Map  of  the  shelf -ice  near  King  Oscar  Land 225 

118.  West-ice  seen  from  the  "  Gauss  "  off  Kaiser  Wilhelm  Land          .  228 

119.  Junction  of  the  "  West-ice  "  and  the  "  sea-ice  "  228 

120.  Diagram  showing  manner  of  formation  of  "  West-ice  "  mass         .  230 

121.  Map  of  the  glaciers  and  shelf-ice    tongues  about   the   head   of 

Robertson  Bay,  Victoria  Land 230 

122.  Map  showing  the  shelf-ice  tongues  on  the  west  of  Ross  Sea  with 

the  glacier  outlets  above  them 232 

123.  Ideal  section  through  a  shelf -ice  tongue 233 

124.  The  ice  barrier  breaking  away  to  form  a  tabular  and  rectangular 

berg 235 

125.  Rectangular  and  tabular  berg  of  Antarctic  waters         .         .         .     236 

126.  Tabular  Antarctic  iceberg,  showing  perpendicular  and  rectangu- 

lar jointing 236 

127.  View  of  a  tilted  tabular  berg,  showing  the  rectangular  lines  in 

the  plan 237 

128.  The  inland-ice  of  Kaiser  Wilhelm  Land  seen  from  the  sea    .        .    246 

129.  Intersecting  series  of  fissures  in  the  surface  of  the  inland-ice  of 

Kaiser  Wilhelm  Land 247 

130.  Section  across  the  margin  of  the  inland-ice  of  Victoria  Land  to 

the  westward  of  McMurdo  Sound 253 

131.  a,  b.  Section  across  the  Great  Ross  Barrier  and  up  the  Beardmore 

Outlet  to  the  ice  plateau ;  c.  Section  across  the  Drygalski  ice- 
barrier  tongue  and  up  the  Backstairs  Passage  to  the  inland-ice     254 


xxiv  ILLUSTRATIONS  IN  THE  TEXT 


132.  A  comparison  of  sections  across  the  margin  of  the  Greenland 

and  Antarctic  continental  glaciers      ......     255 

133.  View  from  above  the  Ferrar  Outlet,  showing  the  dip  of  the  sur- 

face from  indraught  of  the  ice     .......     256 

134.  Map  of  the  Beardmore  Outlet 258 

135.  Map  showing  sastrugi  on  David's  route  to  the  south  magnetic 

pole 267 

136.  Lee  side  of  a  sand  dune,  showing  curve  of  profile  .         ,  •'..*'     .     273 

137.  Profile  across  the  ice-cap  of  the  Vatna  Jokuli         ....     274 

138.  Section  of  one  of  the  irregular  ice  grains  enveloped  in  water 

which  was  precipitated  together  with  snowflakes  upon  inland- 
ice  of  Northeast  Land          ..        ..        ..         .         •     277 

139.  Sketch  map  showing  glaciated  and  higher  non-glaciated  surfaces 

of  the  rock  masses  which  protrude  through   the  ice  in  the 
vicinity  of  McMurdo  Sound 279 

140.  Diagram  to  illustrate  the  growth  of  an  inland-ice  mass  through 

the  rhythmic  action  of  the  anti-cyclonic  air-engine    .        .        .    288 


CHARACTEEISTICS 

OF 

EXISTING    GLACIERS 


CHARACTERISTICS    OF    EXISTING 
GLACIERS 

INTRODUCTION 

The  Ancestry  of  Glacial  Theories.  —  If  we  are  to  gauge 
the  generally  accepted  hypotheses  of  any  science  and  arrive 
at  individual  conclusions  respecting  their  value,  we  must 
be  prepared  to  inquire  into  the  ancestry  of  each  —  we  must 
trace  out  the  route  by  which  each  has  come  to  its  present 
position  of  eminence.  It  is  a  Scriptural  saying  that  "  we 
see  through  a  glass  darkly ,"  and  scientific  reasoning,  we 
know,  makes  a  demand  upon  the  imagination.  To  a  solid 
basis  of  observation,  which  at  best  but  half  discloses  the 
truth,  inductive  reasoning  is  to  be  added  if  science  is  to 
advance. 

Psychological  processes  and  the  tendencies  of  scientific 
thought  are  thus  to  be  well  considered  by  the  more  thought- 
ful student  of  science  in  forming  his  opinions.  Experience 
has  shown  that  whenever  a  new  and  more  advanced  view- 
point has  been  gained  to  take  the  place  of  an  earlier  one, 
and  its  superiority  has  come  to  be  acknowledged,  the  ten- 
dency has  always  been  to  sketch  in  from  that  one  standpoint 
even  the  more  distant  objects,  rather  than  to  move  forward 
to  new  and  independent  positions.  This  has  been  no  less 
true  of  glacier  study  than  of  the  broader  divisions  of  science. 
This  general  fact  is,  perhaps,  in  part  to  be  explained  by  the 
optimism  inherent  in  human  nature;  but  account  must  also 
be  taken  of  the  authority  of  a  great  name  in  science. 


2  CHARACTERISTICS  OF  EXISTING  GLACIERS 

With  the  multiplication  of  workers  which  is  characteristic 
of  present-day  science,  the  number  of  authorities  increases 
and  the  servile  attitude  within  the  profession  toward  its 
great  leaders  will  gradually  disappear.  The  student  of 
geology  would,  however,  do  well  to  take  note  of  the  early 
dominant  influence  of  Werner  or  von  Buch  in  Germany,  of 
de  Beaumont  in  France,  of  Murchison  in  England,  or  of 
Agassiz,  the  "  Pope  of  American  Science." 

It  is  a  truism  that  the  influence  of  things  seen  is  more 
potent  than  that  of  things  merely  heard  of  or  read  about. 
The  unconscious  effect  of  the  immediate  environment,  of 
oft  present  scenes,  in  directing  the  trend  of  thought,  and  of 
determining  convictions,  is  an  unwritten  chapter  in  the 
philosophy  of  science.  It  would  be  easy  to  show  how  all 
the  accepted  views  of  geological  processes  would  have  been 
different  had  the  seats  of  learning  been  located  either  in  the 
tropics  or  in  polar,  rather  than  temperate,  latitudes.  More- 
over, it  has  not  always  been  easy  to  say  what  observed  phe- 
nomena are  of  general  and  what  are  of  only  local  importance. 
Environment  is,  therefore,  of  the  utmost  importance  in  the 
evolution  of  the  "  body  of  doctrine  "  of  any  science. 

To  apply  these  considerations  to  glacial  theories,  we 
find  that  whereas  existing  glaciers  are  found  in  all  latitudes, 
but  with  the  largest  and  most  important  types  in  polar  and 
sub-polar  regions;  the  earliest  and  by  far  the  largest  number 
of  studies  have  been  made  in  the  Alps,  where  a  single  type 
of  small  glacier  is  found.  The  reason  is  not  far  to  seek. 
The  Alps  have  now  for  a  good  many  years  been  the  play- 
ground of  Europe  easily  reached  and  explored  by  her  scien- 
tific men. 

Until  the  close  of  the  eighteenth  century  there  existed 
a  popular  belief  that  the  mountain  highlands  were  bewitched. 
The  Alps  were  the  montagnes  maudits  and  in  consequence 
a  terra  incognita.  It  was  de  Saussure  who  both  by  precept 


INTRODUCTION  3 

and  example  as  well  as  by  offering  a  generous  prize,  stimu- 
lated interest  in  exploring  the  Alps  and  thus  dispelled  the 
illusions  which  had  so  long  clung  to  them.  We  may  here 
pass  over  his  scientific  conclusions,  as  we  may  over  those  of 
Scheuchzer,  Hugi,  Venetz,  and  other  early  workers,  impor- 
tant as  they  were;  for  it  was  not  until  the  early  forties  of 
the  nineteenth  century  when  Agassiz  l  and  Charpentier 2 
published  their  important  monographs  upon  the  physiog- 
raphy, the  structure,  the  mechanical  work,  and  the  former 
extensions  of  the  Alpine  glaciers,  that  a  lively  interest  was 
excited  in  them. 

This  sudden  interest  in  glaciers  on  the  part  of  geologists 
arose,  not  so  much  because  of  an  interest  in  the  Alpine  glaciers 
themselves,  as  for  the  reason  that  on  the  basis  of  these  studies 
Agassiz  soon  founded  his  theory  of  the  ice  age,  and  was  thus 
for  the  first  time  able  satisfactorily  to  explain  the  origin  of 
the  erratic  blocks  which  are  found  strewn  over  the  Alpine 
foreland,  the  North  German  plain,  the  British  Isles,  and 
Northern  North  America.  The  great  continental  glaciers 
which  he  thus  hypothecated  were  from  a  thousand  to  a 
millionfold  greater  than  those  ice  masses  which  had  been 
seen  and  studied,  from  which  ice  masses  they  must  have 
differed  most  widely.  This  is  particularly  true,  as  we  now 
know,  as  concerns  their  physiographic  development  and 
their  alimentation.  No  continental  glaciers  being  then 
known,  it  was  but  natural  that  the  attributes  of  Alpine 
glaciers  should  have  been  carried  over  to  the  continental 
type  thus  reconstructed  in  imagination  upon  the  basis  merely 
of  its  carvings,  its  gravings,  and  its  deposits. 

It  is  one  of  the  strange  coincidences  of  science  that  almost  at 
the  moment  when  the  epoch-making  studies  of  Agassiz  were 
being  made  upon  Swiss  glaciers,  three  great  scientific  explor- 
ing expeditions  were  independently  discovering  the  greatest 
of  existing  continental  glaciers,  that  of  Antarctica,  but  with- 


4  CHARACTERISTICS  OF  EXISTING  GLACIERS 

out  being  able  to  set  foot  upon  it  or  to  learn  aught  of  its 
characters.  Thus  it  happened  that  the  views  concerning 
continental  glaciers  took  shape  before  any  had  been  visited, 
and  one  result  is  that  even  to-day  in  university  and  college 
texts  we  find  the  attributes  of  continental,  Alpine,  and  other 
glacier  types  classified  together  as  though  all  were  necessarily 
identical  in  origin. 

The  first  attempt  to  arrive  at  observational  knowledge  of 
"  inland-ice  "  was  the  expedition  of  Otto  Torell  to  Spitz- 
bergen  in  1858.  It  was  the  unsuccess  of  the  Swedish  polar 
expedition  of  1872-1873  which  made  the  journey  by  Norden- 
skiold  and  Palander  across  Northeast  Land  (Spitzbergen) 
the  first  successful,  comprehensive  attempt  to  observe  any 
considerable  area  of  inland-ice.  It  will,  however,  hardly 
be  claimed  that  the  results  of  this  expedition  are  well  known, 
or  that  they  have  in  any  important  way  influenced  glacial 
theories.  The  later  discoveries  of  Nordenskiold,  Nansen, 
and  above  all  Peary  on  the  great  continental  glacier  of 
Greenland,  rich  as  they  are  in  results,  are,  moreover,  not  as 
well  known  as  they  should  be,  and  are  only  beginning  to 
modify  the  views  held  concerning  continental  glaciers. 
In  fact,  it  is  only  toward  the  beginning  of  the  twentieth 
century  that  former  continental  glaciers  have  begun  to  be 
studied  on  the  basis  of  any  other  model  than  the  Alps. 

The  Factor  of  Air  Temperature.  —  With  the  advance  of 
knowledge  concerning  the  sequence  of  conditions  affecting 
glaciers,  it  has  come  to  be  quite  generally  recognized  that 
for  any  given  district  the  factor  of  supreme  importance  in 
initiating  glaciation  is  temperature;  a  very  moderate  change 
in  the  average  annual  temperature  being  sufficient  to  trans- 
form a  district,  the  aspect  of  which  is  temperate,  and  to 
furnish  it  with  snow-fields  and  mountain  glaciers.  Thus 
it  has  recently  been  estimated  that  a  fall  of  but  3°  F.  in  the 
average  annual  temperature  of  Scotland  would  result  in  the 


INTRODUCTION  5 

formation  of  small  glaciers  within  the  area  of  the  Western 
Highlands,  while  a  like  fall  of  12°  F.  within  the  Laurentian 
Lake  district  of  North  America  would  be  sufficient  to  bring 
on  a  period  of  glaciation. 

It  is  further  of  interest  that  such  temperature  changes 
affect  the  distribution  of  air  pressure  over  the  continents  and 
in  this  or  in  other  ways  directly  modify  the  precipitation  of 
moisture.  Statistics  have  shown  that  cold  periods  corre- 
spond to  high  precipitation  and  warm  periods  to  smaller  falls 
of  snow  and  rain.3  It  is  further  found  that  the  larger  cli- 
matic changes  are  common  to  very  large  areas  of  the  earth  4 
and  are  probably  world  wide  in  their  extent.5 

In  climates  such  as  now  prevail  on  the  borders  of  Ant- 
arctica, it  is  true  that  most  of  the  snow  falls  in  the  warmer 
season.  Gourdon  has  apparently  been  misled  by  this  into 
believing  that  warm  rather  than  cold  climates  promote 
glaciation.6  As  we  shall  see,  glaciers  are  under  these  condi- 
tions nourished  by  a  different  process,  which  is  in  a  large 
measure  independent  of  local  evaporation. 

With  the  probability  that  such  progressive  climatic 
changes  would  be  initiated  slowly,7  the  first  visual  evidence 
of  the  changing  condition  within  all  districts  of  accentuated 
relief  would  probably  be  a  longer  persistence  of  winter  snows 
in  the  more  elevated  tracts;  which  accumulation  of  snow 
would  eventually  contribute  a  remnant  to  those  of  the  suc- 
ceeding winters,  and  so  bring  on  a  period  of  glaciation.  Such 
a  change  of  air  temperatures  with  resultant  changes  in  snow 
precipitation  may  be  otherwise  expressed  as  a  depression  of 
the  snow-line  of  the  district.  All  are  familiar  with  the  fact 
that  as  we  ascend  in  the  atmosphere  we  pass  into  succes- 
sively colder  strata.  Mountains  which  even  in  tropical 
regions  push  up  their  heads  to  great  altitudes,  are  in  conse- 
quence capped  with  snow  throughout  the  year.  The  snow- 
line  is  the  lower  limit  of  this  "  perpetual "  snow,  and  it  is 


6  CHARACTERISTICS  OF  EXISTING  GLACIERS 

evident  that  any  refrigeration  of  the  atmosphere  will  cause 
the  line  to  descend  toward  the  lower  levels.8 

From  this  beginning  the  process  is  an  advancing  one  until 
a  culmination  of  glaciation  is  attained  corresponding  to  the 
most  rigorous  of  the  climatic  conditions.  A  resumption  of 
a  more  genial  climate  would  bring  about  a  reverse  series  of 
changes,  a  waning  of  the  glaciers  setting  in  so  soon  as  the 
winter's  fall  of  snow  is  insufficient  to  contribute  a  remnant 
to  succeeding  seasons.  It  is,  therefore,  proper  to  speak  of 
advancing  and  receding  hemicycles  of  glaciation. 8o 

This  use  of  the  expression  cycle  of  glaciation  carries  with 
it  no  idea  of  lapse  of  time  except  such  as  is  implied  in  the 
completion  of  a  progressive  series  of  climatic  changes,  and  a 
return  to  the  initial  condition.  In  any  given  district  the 
time  may  have  been  insufficient  to  accomplish  the  complete 
normal  series  of  denudational  results  indicated  in  neighboring 
districts  which  were  more  favored  in  respect  to  glacier  nour- 
ishment. The  term  "  cycle  of  glaciation "  is,  therefore, 
not  the  equivalent  of  "  glacial  cycle  "  used  by  Professor 
Davis,9  since  in  our  use  the  cycle  is  measured  in  climatic 
changes  rather  than  in  the  attainment  of  certain  denudational 
effects  within  the  glaciated  valleys.  Russell's  earlier  discus- 
sion of  the  "  Life  History  of  a  Glacier  " 10  takes  account  of 
this  alternation  of  sequential  climatic  changes  —  a  climatic 
episode  —  with  resultant  changes  in  the  size  and  physio- 
graphic forms  of  glaciers. 

Mountain  versus  Continental  Glaciers.  —  Those  glaciers 
which  are  developed  in  mountain  districts  differ  from  the 
ice  masses  of  the  interiors  of  continents  or  islands  in  several 
important  particulars.  As  respects  their  physiographic 
forms,  they  are  as  different  as  possible.11  Inland-ice  assumes 
a  form  the  visible  surface  of  which  is  largely  independent 
of  the  basement  upon  which  it  rests,  while  there  is  no  definite 
model  to  which  the  glaciers  of  mountains  conform,  they 


INTRODUCTION  7 

being  moulded  with  reference  to  the  irregularities  of  their 
beds.  It  is  characteristic  of  inland-ice  that  no  portion  of  the 
lithosphere  is  exposed  above  its  higher  levels.  The  glaciers 
of  mountains,  on  the  contrary,  always  have  rock  exposed  above 


FIG.  1.  —  Ideal  section  across  inland-ice. 

their  highest  levels.  The  physiographic  form  assumed  by 
inland-ice  is  invariably  that  of  a  flat  dome  or  shield,  and  all 
visible  projections  of  the  lithosphere  within  the  area  of  the 
ice  are  restricted  to  the  marginal  zone  (see  Fig.  1).  The 
glaciers  of  mountains,  as  already  stated,  conform  to  no  definite 
model,  and  rock  projections  may  appear  at  any  level,  but  are 
always  to  be  seen  above  the  highest  levels  (see  Fig.  2  and  pi.  1). 


FIG.  2.  —  Section  across  a  mountain  upland  occupied  by  glaciers  with  the  glaciers 

in  black  (after  Hess). 

The  unique  exception  to  this  law  is  the  small  ice-cap  or  plat- 
eau glacier  which  is  transitional  between  inland-ice  and 
mountain  glaciers  (see  Fig.  3).  In  size  more  nearly  allied 


FIG.  3.  —  View  of  the  ice-cap  of  the  Eyriksjokull,  Iceland,  seen  from  the  West 

(after  Grossman 12). 

to  the  glaciers  of  mountains,  in  form  the  ice-cap  resembles 
the  masses  of  inland-ice  —  it  is  developed  as  a  flat  dome  or 


g  CHARACTERISTICS  OF  EXISTING  GLACIERS 

shield.  As  regards  the  processes  by  which  they  are  nour- 
ished, ice-caps  are,  however,  as  will  be  seen,  quite  different 
from  true  inland-ice;  and  they  should  in  consequence  be 
considered  separately  and  in  order  between  the  others,  so 
as  to  call  attention  to  their  intermediate  position.  Their 
size  is  usually  a  direct  consequence  of  the  limitations  of  the 
circumscribed  area  of  the  rock  platform  upon  which  they 
rest  —  usually  either  a  small  island  or  a  limited  portion  of 
a  high  plain  or  plateau.  The  regular  surface  form  common  to 
inland-ice  and  ice-caps  is  due  to  the  fact  that  the  irregularities 
of  the  base  are  small  when  compared  with  the  dimensions  of 
the  ice  mass.  The  ice-caps  of  Norway  or  Iceland  have  in 
common  with  the  glaciers  of  mountains,  a  considerable 
elevation  above  the  sea,  but  the  variations  of  their  base 
from  a  horizontal  plane  are  small  by  comparison  with  the 
other  dimensions.  Curiously  enough  there  is  to  this  rule  a 
single  exception,  and  here  it  is  not  the  flatness  of  the  base  but 
the  precipitousness  of  platform  slope  which  is  the  determining 
factor.  This  special  case  is  of  ice-caps  on  the  high  volcanic 
peaks  of  low  latitudes,  which  on  excessively  steep  slopes 
push  their  summits  far  into  the  upper  atmospheric  strata. 

Low  Level  versus  High  Level  Sculpture.  —  In  part  the 
failure  to  note  the  essential  difference  between  mountain 
glaciers  and  inland-ice  is  due  to  the  peculiar  evolution  of 
glacier  studies  which  has  been  outlined  in  the  introduction, 
but  in  part  it  is  to  be  explained  by  a  rather  general  tendency 
to  treat  the  subject  of  erosion  by  glaciers  in  mountains  from 
studies  made  especially  in  the  lower  altitudes.13  A  quite 
general  neglect  of  those  special  conditions  of  denudation 
which  are  operative  in  high-level  areas  of  glaciers  is,  it  is 
believed,  responsible  for  an  over-emphasis  laid  upon  the 
U-shaped  trunk  valley  and  the  hanging  tributary  valley, 
important  as  these  features  are.14  This  over-emphasis  can, 
perhaps,  be  best  illustrated  by  reference  to  a  series  of  three 


INTRODUCTION  !    9 

successive  idealistic  sketches,  executed  with  great  skill  by 
an  eminent  American  geographer,  and  intended  to  develop 
especially  the  erosion  forms  which  result  from  mountain 
glaciers.15  The  low-level  sculpturing  expressed  by  these 
sketches  is,  in  the  opinion  of  the  writer  admirable  and  a 
true  rendering  of  nature.  It  is  the  failure  to  recognize  any 
additional  process  of  erosion  operative  in  higher  altitudes 
which  destroys  the  value  of  the  high-level  sculpturing  dis- 
played. 

So  far  as  low-level  mountain  glaciation  is  concerned,  the 
erosive  processes  are  pretty  well  understood  to  be  identical 
with  those  of  continental  glaciers,  namely,  abrasion  and 
plucking.  The  former  process  is  a  wearing  away  of  the  rock 
surface  which  is  in  every  way  analogous  to  the  abrasion  of  a 
facet  upon  a  gem  by  a  lapidary,  the  stones  frozen  into  the 
mass  of  the  ice  corresponding  to  the  diamond  dust  imbedded 
in  the  lap.  The  product  of  glacial  abrasion  is  rock  flour. 
The  plucking  process,  on  the  other  hand,  is  a  removal  of  the 
rock  in  larger  masses  aided  often  by  the  fracture  planes 
already  present,  which  so  often  bound  the  dislodged  masses. 
In  parts  of  a  glacier  bed  recently  uncovered  near  the  glacier 
foot,  the  dislodged  blacks  may  sometimes  be  fitted  into  the 
rock  floor  from  which  they  have  been  extracted.16  With 
respect  to  the  direction  of  movement  of  the  ice,  abrasion  is 
particularly  developed  on  obstructing  rock  masses  on  the 
side  from  which  the  ice  comes  —  stoss  side,  and  plucking 
upon  the  side  away  from  which  it  moves  —  the  lee  side. 
The  two  sides  of  an  obstruction  in  the  bed  have  therefore 
been  called  the  "  scour  "  side  and  the  "  pluck"  side.17  The 
plucking  process  is  no  doubt  in  some  cases  much  facilitated 
by  a  ready  separation  of  the  rock  along  planes  parallel  to 
the  surface,  these  planes  being  due  to  the  strains  set  up  in 
the  rock  parallel  to  its  free  surface. 

To  these  processes  of  abrasion  and  plucking  there  is  in  the 


10          CHARACTERISTICS  OF  EXISTING  GLACIERS 

case  of  mountain  glaciers  a  third  important  denuding  process 
which  may  locally  be  more  important  than  both  the  others 
acting  together.  It  is  this  process  of  head-wall  erosion  which 
as  regards  reaction  with  the  lithosphere  differentiates  all 
types  of  mountain  glaciers  from  continental  ones.  This 
distinguishing  process  is  responsible  for  the  development  of 
the  cirque  (Ger.  cirkus),  which  is  known  by  a  variety  of 
names  in  different  glacier  districts.  In  Scotland  it  has  been 
generally  referred  to  as  the  come,  in  Wales  as  the  cwnij  and  in 
Scandinavia  as  the  botn  or  kjedel  (kessel).  In  the  scientific 
literature  of  the  subject  the  Bavarian- Austrian  word  "kahr" 
has  been  used  with  increasing  frequency  for  the  same 
topographic  feature. 

In  view  of  this  diversity  in  resultant  topography,  and 
despite  their  close  genetic  relationships,  we  would  do  well  to 
sharply  separate  in  our  discussions  continental  glaciers  from 
the  other  types,  which  latter  we  may  include  under  the  broad 
term  of  " mountain  glaciers." 

REFERENCES 

1  L.  Agassiz,   "Etudes  sur  les  glaciers,"  Neuchatel,  1840,  pp.  1-346. 
Accompanied  by  an  atlas  of  32  plates.     An  even  more   comprehensive 
monograph  Agassiz  published  in  1847  under  the  title,  "Nouvelles  etudes 
et  experiences  sur  les  glaciers  actuels,  leur  structure,  leur  progression,  et 
leur  action  physique  sur  le  sol,"  Paris,  1847,  pp.  1-598.    With  an  atlas 
of  3  maps  and  9  plates  (generally  referred  to  as  "System  Glaciare"). 

2  Jean  de  Charpentier,  "  Essai  sur  les  glaciers  et  sur  le  terrain  erratique 
du  bassin  du  Rhone,"  Lausanne,  1841,  pp.  1-363.     Map  and  plates. 

3  Eduard  Bruckner,  "  Klimaschwankungen  und  Volkerwanderungen  im 
xix.  Jahrhundert,"  I  tern.  Wochensch.  f.  Wissenschaft,  Kunst  und  Technik, 
March  5,  1910,  p.  6. 

4  Siegfried  Passage,  "Die  Kalihari,"  Berlin,  1904,  p.  662.     A.  Penck, 
"Climatic  Features  of  the  Ice  Age,"  Geogr.  Jour.,  vol.  22,  1906,  pp.  185- 
186.     Ellsworth  Huntington,  "Some  Characteristics  of  the  Glacial  Period 
in  Non-glaciated  Regions,"  Bull.  Geol.  Soc.  Am.,  vol.   18,  1907,  pp.  351- 
388,  pis.  31-35.     Ellsworth  Huntington,  "The  Pulse  of  Asia,"  New  York 
and  Boston,  1907,  pp.  i-xxi,  1-415.     Ellsworth  Huntington,  "The  Libyan 
Oasis  of  Kharga,"  Bull.  Am.  Geogr.  Soc.,  vol.  42,  1910,  pp.  660-661. 

5  Frank  Leverett,   "Comparison  of   North   American   and  European 
glacial  deposits,"  Zeitsch.  f.  Gletscherk,  vol.  4,  1910,  pp.  241-316. 


INTRODUCTION  11 

6  "It  is  in  fact  the  proportion  of  water  vapor  in  the  air  which  con- 
trols the  greater  or  less  abundance  of  snow  precipitation,  so  that,  as 
Tyndall  has  remarked,  it  is  the  solar  action  which  is  necessary  to  bring 
on  the  initial  condition;  the  conclusion,  which  appears  paradoxical  at 
first,  is  the  following,  that  the  warmest  periods  determine  more  active 
evaporation  of  the  ocean  water ;  it  is  to  them  that  the  greatest  extensions 
of  glaciation  correspond.  Cold  plays  the  merely  passive  role  of  condenser." 
(Gourdon,  Exped.  Ant.  Frang.,  1903-1905,  Glaciologie,  1908,  p.  70.) 

7 1.  C.  Russell,  "Climatic  Changes  indicated  by  the  Glaciers  of  North 
America,"  Am.  Geol.,  vol.  9,  1892,  p.  336. 

8  A.  Penck,  "Climatic  Features  of  the  Pleistocene  Ice  Age,"  Geogr. 
Jour.,  vol.  27,  1906,  pp.  182-187. 

8a  William  Herbert  Hobbs,  "  The  Cycle  of  Mountain  Glaciation,"  Geogr. 
Jour.,  vol.  36,  1910,  pp.  146-163,  268-284,  36  figs. 

9  W.  M.  Davis,  "Glacial  Erosion  in  France,  Switzerland,  and  Norway," 
Proc.  Bos.  Soc.  Nat.  Hist.,  vol.  29,  1900,  pp.  294-300. 

10 1.  C.  Russell,  "Glaciers  of  North  America,"  1897,  pp.  190-206. 

11 E.  v.  Drygalski  says :  "The  difference  between  glaciers  and  inland  ice 
is  essentially  a  quantitative  one.  Glacier  forms  are  small,  inland  ice 
masses  great  glaciations.  .  .  .  Inland  ice  masses  are  ice  overflows  of 
entire  earth  surfaces,  glaciers  are  branching  outflow  systems  for  snow 
deposits  guided  by  the  features  of  the  earth's  surface."  In  Keilhack's 
"Lehrbuch  der  praktischen  Geologie,"  1908,  p.  269. 

12  Karl  Grossmann,  "Observations  on  the  glaciation  of  Iceland,"  Gla- 
cialists'  Magazine,  vol.  1,  No.  2,  1893,  pi.  3,  fig.  2. 

13  "The  visitor  replied  that  he  was  a  valley  climber,  not  a  mountain 
climber.     He  found  sufficient  pleasure  at  the  mountain  base,  and  such 
was  my  case  also.     Mountain  tops  are  indeed  worthy  objects  of  a  climb- 
er's ambition,  but  if  one  wishes  to  get  at  the  bottom  facts,  let  him  ex- 
amine the  valleys."     (W.  M.  Davis,  "Glacier  Erosion  in  the  Valley  of 
the  Ticino,"  Appalachia,  vol.  9,  1901,  p.  137.) 

14  On  hanging  valleys,  see  especially  W.  M.  Davis,  Proc.  Bos.  Soc.  Nat. 
Hist.,  vol.  29,  1901,  pp.  273-322;   and  G.  K.  Gilbert,  "Glaciers,"  Harri- 
man  Alaska  Expedition,  vol.  3. 

15  W.   M.   Davis,   "The   Sculpture  of  Mountains  by  Glaciers,"   Scot. 
Geogr.  Mag.,  vol.  22,  1906,  figs.  1-3. 

16  Ed.  Bruckner,  "  Die  Glacialen  Ziige  im  Antlitz  der  Alpen,"  Naturw. 
Wochensch.,  N.  F.,  vol.  8,  1909,  p.  792. 

17  Penck,  "Glacial  Features  in  the  Surface  of  the  Alps,"  Jour.  GeoL, 
vol.  13,  1905,  p.  6. 


PART   I 

MOUNTAIN  GLACIERS 

CHAPTER   I 
THE  CIRQUE  AND   ITS  RECESSION 

The  Glacial  Amphitheatre  in  Literature.  —  It  is  safe  to 
say  that  no  topographic  feature  is  more  characteristic  of  the 
mountains  which  have  been  occupied  by  glaciers  than  is  the 
cirque.  Approaching  a  range  from  a  considerable  distance, 
there  is  certainly  no  feature  which  so  quickly  forces  itself 
upon  the  attention.  The  U-shaped  valley  and  the  hanging 
side  valley,  important  as  these  are,  are  here  decidedly  less  im- 
pressive. Yet  the  great  majority  of  works  upon  the  subject, 
by  ignoring  the  significance  of  the  cirque,  allow  the  reader  to 
assume  that  the  glaciers  discovered  the  cirques  ready  formed 
to  gather  in  the  snows  for  their  nourishment.  Even  the 
standard  work  of  Chamberlin  and  Salisbury  is  open  to  this 
objection.1 

Despite  the  attitude  of  the  general  texts,  which  so  largely 
determine  what  might  be  called  the  accepted  body  of  doc- 
trine of  a  science,  there  are  a  number  of  papers  dealing  with 
the  origin  of  the  cirque.  One  of  the  first  to  recognize  the 
cirque  as  a  product  of  glacial  erosion  was  Tyndall,  whose  keen 
mind  has  so  illumined  the  page  of  mountain  glaciation.2  In 
opposition  to  his  view,  Bonney  published  in  1871  a  somewhat 
elaborate  article,  in  which  the  line  of  argument  was :  (1)  that 
the  Alpine  cirques  must  have  been  produced  by  the  agency 

12 


THE  CIRQUE  AND  ITS  RECESSION  13 

which  shaped  the  valleys  below  them;  (2)  that  the  valleys 
were  not  moulded  by  glaciers;  and  hence,  (3)  the  cirques 
must  have  been  retained  from  the  pre-glacial  land  surface.3 
The  published  discussion  of  this  paper  developed  no  oppo- 
sition to  the  view,  though  Doctor,  now  Sir  Archibald,  Geikie 
stated  that  he  could  not  see  his  way  to  account  for  the  vertical 
walls  surrounding  the  cirque.  On  the  other  hand,  the  Italian 
Professor  Gastaldi  recognized  the  work  of  the  ice  in  the  shap- 
ing of  cirques  in  the  Italian  Alps,4  as  Helland  did  in  those  of 
Norway.  The  latter  believed  that  excessive  weathering  in 
the  rock  above  the  neve  played  an  important  role,  though  ab- 
rasion by  the  ice  upon  the  floor  was  the  larger  factor.5  Later 
Russell  in  America,6  Wallace  in  England,7  and  de  Martonne 
upon  the  continent,8  further  advocated  the  glacial  origin  of 
cirques.  Penck  has  explained  the  development  of  cirques 
as  the  result  of  sub-glacial  weathering  —  alternate  thawing 
and  freezing  —  beneath  glaciers  during  the  incipient  stage 
particularly  ("  hanging  glaciers  ").9  This  eroding  process, 
he  considered,  would  be  greatest  toward  the  middle  of  the 
glacier,  so  that  the  original  concavity  of  the  slope  beneath  it 
would  be  more  and  more  deepened.  It  must  be  evident 
that  this  explanation  does  not  properly  account  for  the  steep- 
ness of  the  cirque  walls,  which  it  will  be  remembered  could 
not  be  accounted  for  by  Geikie. 

Attention  was  again  directed  to  the  process  of  cirque  shap- 
ing by  an  important  paper  of  Richter's  published  in  1896.10 
His  studies  having  been  made  in  Norway,  where  a  country 
rounded  and  polished  by  the  continental  glacier  had  been 
only  partly  invested  by  mountain  glaciers,  the  cirques  from 
the  latter  formed  individual  "  niches  "  in  the  uplands.  Fol- 
lowing Gastaldi,  the  form  of  these  niches  was  happily  likened 
to  that  of  an  armchair  (see  Fig.  4).11  Richter  observed  that 
the  steep  walls  of  the  cirque  were  the  only  surfaces  ungla- 
ciated,  and  hence  he  concluded  that  they  were  not  to  be 


14          CHARACTERISTICS  OF  EXISTING  GLACIERS 

ascribed  to  ice-abrasion,  but  to  weathering.  The  moulding 
of  the  cirque  floor  he  ascribed  to  abrasion,  and,  referring  to 
the  cirque  walls,  said  - 

The  material  loosened  by  weathering  is  removed  by  the  gla- 
cier or  slides  off  over  the  neve  to  form  either  actual  moraines, 
or,  at  least,  neve  moraines.  These  walls  do  not  bury  themselves 
in  their  own  debris,  and  in  consequence  continually  offer  fresh 
surfaces  for  attack.  Finally,  the  wearing  away  of  the  cirque 
floor  by  the  glacier  cooperates  to  keep  the  cirque  walls  on  a 
steep  angle  and  facilitates  avalanching. 


FIG.  4.  —  Cirque  excavated  in  the  glaciated  surface  of  Norway,  Northern  Kjedel 
on  Galdhopig  (after  E.  Richter). 

In  a  more  extended  and  later  paper,12  treating  especially 
the  formation  of  cirques,  Richter  has  explained  that  his  view 
differs  from  that  of  Helland  only  in  ascribing  greater  impor- 
tance to  weathering  upon  the  cirque  walls  and  less  to  abrasion 
upon  the  cirque  floor.  Inasmuch  as  the  excessive  weather- 
ing of  cirque  walls,  as  maintained  by  Richter,  is  above  the  sur- 
face of  the  neve,  a  horizontal  plane  of  denudation  should 
develop  at  that  level.  No  evidence  of  this  plane  being  dis- 
covered, its  absence  is  explained  by  Richter  through  abra- 
sion from  the  snowbank  which  would  collect  upon  it  so 
soon  as  formed.  This  is  the  fatal  weakness  of  the  Richter 
hypothesis. 

Relation  of  Cirque  to  Bergschrund. — Up  to  the  beginning 
of  the  twentieth  century,  as  we  have  seen,  few  geologists  had 


THE  CIRQUE  AND  ITS  RECESSION  15 

greatly  concerned  themselves  with  the  erosion  conditions  at 
high  levels,  the  work  of  Richter  being  on  the  whole  the  most 
comprehensive.  The  whole  subject  of  cirque  erosion  was 
rather  generally  ignored,  as  it  is,  indeed,  to-day.  Sir  Archi- 
bald Geikie,  referring  to  the  corries  of  the  Scottish  High- 
lands,13 wrote  — 

The  process  of  excavation  seems  to  have  been  mainly  carried 
on  by  small  convergent  torrents,  aided,  of  course,  by  the  power- 
ful cooperation  of  the  frosts  that  are  so  frequent  and  so  potent 
at  these  altitudes.  Snow  and  glacier  ice  may  possibly  have  had 
also  a  share  in  the  task. 

Writing  in  the  same  year,  Reusch  ascribed  the  Norwegian 
cirques  to  the  action  of  surface  water  descending  through  the 
crevasses  over  falls  in  the  continental  glacier  which,  in  Pleis- 
tocene times,  overrode  the  country ; 14  and  the  following  year 
Bonney  reiterated  his  view  that  cirques  were  the  product  of 
water-erosion.15  Only  a  few  years  before,  Gannett  had  curi- 
ously explained  the  origin  of  cirques  through  the  wear  of 
avalanched  snow  and  ice  upon  the  cirque  floor,  likening  the 
erosive  process  to  that  which  takes  place  beneath  a  water- 
fall.16 

The  discovery  of  the  method  by  which  the  glacier  exca- 
vates its  amphitheatre  must  be  credited  to  a  keen  American 
topographer-geologist,  Mr.  Willard  D.  Johnson  of  the  United 
States  Geological  Survey.17  In  fact,  to  him  and  to  another 
American  topographer,  Mr.  Francois  E.  Matthes,  we  owe  the 
most  of  what  is  known  from  observation  concerning  the 
initiation  and  developme^fof  the  glacier  cirque.  Reasoning 
that  abrasion  was  incompetent  to  shape  the  amphitheatre, 
Johnson  early  surmised  thatVthe  great  gaping  crevasse  which 
so  generally  parallels  the  cirque  wall  and  is  termed  the 
Bergschrund  (Fr.,  rimaye)  went  down  to  the  rock  beneath 
the  neve,  and  that  it  was  no  accident  that  glaciated  moun- 
tains alone  "  abound  in  forms  peculiarly  favorable  to  snow- 


16          CHARACTERISTICS  OF  EXISTING  GLACIERS 


drift  accumulation  "  (see  Fig.  5).     These  observations  were 
made  as  early  as  1883,  and  in  order  to  test  his  theory,  John- 


FIG.  5.  —  Bergschrund  below  cirque  wall  on  a  glacier  of  the  Sierra  Nevada,  Cali- 
fornia (after  Gilbert). 


THE  CIRQUE  AND  ITS  RECESSION  17 

son  allowed  himself  to  be  lowered  at  the  end  of  a  rope  150 
feet  into  the  Bergschrund  of  the  Mount  Lyell  glacier  until  he 
reached  the  bottom.  He  found  a  rock  floor  to  stand  upon, 
and  rock  extended  up  for  20  feet  upon  the  cliff  side.  We 
may  here  quote  his  terse  sentences,  since  too  little  attention 
has  been  accorded  this  important  observation.18 

The  glacier  side  of  the  crevasse  presented  the  more  clearly 
defined  wall.  The  rock  face,  though  hard  and  undecayed,  was 
much  riven,  the  fracture  planes  outlining  sharply  angular  masses 
in  all  stages  of  displacement  and  dislodgment.  Several  blocks 
were  tipped  forward  and  rested  against  the  opposite  wall  of  ice  ; 
others  quite  removed  across  the  gap  were  incorporated  in  the 
glacier  mass  at  its  base. 

Everywhere  in  the  crevasse  there  was  melting,  and  thin 
scales  of  ice  could  be  removed  from  the  seams  in  the  rock. 
The  bed  of  the  glacier,  elsewhere  protected  from  frostwork, 
was  here  subjected  to  exceptionally  rapid  weathering.  By 
maintaining  the  rock  wall  continually  wet,  and  by  admitting  the 
warm  air  from  the  surface  during  the  day,  diurnal  changes  of 
temperature  here  resulted  in  very  appreciable  mechanical  effects, 
whereas  above  the  neve  only  the  seasonal  effects  were  important. 

This  observation  of  Johnson  is,  it  will  be  observed,  in  con- 
trast with  the  suppositions  of  Richter,  who  believed  that  the 
maximum  sapping  upon  the  cirque  wall  occurred  above  the 
surface  of  the  neve.  The  function  of  the  Bergschrund,  which 
separates  the  stationary  from  the  moving  snow  and  ice  within 
the  neve,  is  thus  found  to  be  of  paramount  importance  in  the 
shaping  of  the  amphitheatre. 

With  the  coming  of  winter  this  process  halts  and  the 
Bergschrund  fills  with  snow,  but  the  following  spring  it  again 
opens,  though  always  a  little  higher  up  and  nearer  to  the 
cirque  wall.  In  this  way  the  blocks  excavated  from  the  base 
of  the  wall  are  the  more  easily  transferred  to  the  moving 
portions  of  the  glacier.19 


18          CHARACTERISTICS  OF  EXISTING  GLACIERS 

The  Schrundline.  —  That  a  sharp  line  is  observable  in  aban- 
doned cirques  separating  the  accessible  from  the  non-scal- 
able portions  of  the  wall,  has  been  pointed  out  by  Gilbert, 
who  has  given  his  support  to  the  view  of  Johnson,  and  con- 
firmed it  by  observations  of  his  own20  (see  Fig.  6).  Penck,  on 


FIG.  6.  —  Schrundline  near  Mt.  McClure  in  the  Sierra  Nevadas  of  California. 
Above  the  Schrundline  it  is  too  steep  for  snow  to  rest,  and  the  drifts  are  ac- 
cordingly below  this  level  (after  Gilbert). 

the  other  hand,  the  following  year  revived  the  view  of 
Richter  that  excessive  sapping  occurs  upon  the  cirque  walls 
above  the  neve  surface,21  though  he  calls  in  the  Bergschrund  in 
order  to  gather  in  and  remove  the  rock  fragments  which  fall 
from  the  cliff.22 

Initiation  of  the  Cirque,  Nivation. — Johnson's  studies  upon 
the  processes  of  cirque  shaping,  had  shown  how  a  nearly 
perpendicular  cirque  wall  is  steadily  cut  backward  through 
basal  sapping  at  the  bottom  of  the  Bergschrund.  The  prob- 
lem of  how  the  snowbank,  which  was  the  inevitable  forerun- 
ner of  the  glacier,  had  transformed  the  relatively  shallow 


THE  CIRQUE  AND  ITS  RECESSION  19 

depression  which  it  presumably  discovered  into  the  steep- 
walled  amphitheatre,  he  did  not  attempt  to  solve.  Yet  the 
nourishing  catchment  basin  is  a  prerequisite  to  the  existence 
of  the  normal  glacier.  The  solution  of  this  problem  has  been 
suggested  by  another  American  topographer,  Mr.  F.  E. 
Matthes.23  In  the  Bighorn  mountains  of  Wyoming  he  has 
found  exceptional  opportunities  for  this  study.  Owing  to 
the  low  precipitation  within  the  region  and  the  consequently 
inadequate  nourishment  of  glaciers,  a  large  part  of  the 
pre-glacial  surface  still  remains.  There  is,  therefore,  repre- 
sented within  the  district  every  gradation  from  valleys 
which  were  occupied  by  snow  during  a  portion  only  of  the 
year  to  those  which  were  the  beds  of  glaciers  many  miles  in 
length.  Both  small  glaciers  and  high-level  drifts  of  snow 
still  remain  in  a  number  of  places. 

Mr.  Matthes  has  demonstrated  that  the  snowbanks  with- 
out movement  steadily  deepen  the  often  slight  depressions 
within  which  they  lie  by  a  process  which  he  has  called  "niva- 
tion  "  -  excessive 
frost-work  about 
the  receding  mar- 
gins  of  the  drifts 
during  the  sum- 
mer season.  The 
ground  being  con- 
tinually moist  in 
this  belt  due  to 

the  melting  Of   the    FIG.  7.  —  Cross  section  of  a  snowdrift  site  on  a  slope 
cnnw       tVi<=>       wafpr          showing  formation    of    niche     by    nivation    (after 
LOW>  Matthes). 

penetrates        into 

every  crevice  of  the  underlying  rock,  so  that  it  is  rent  dur- 
ing the  nightly  freezing.  Rock  material  thus  broken  up 
and  eventually  comminuted,  is  removed  by  the  rills  of 
water  from  the  melting  snow.24  By  this  process  the  original 


20          CHARACTERISTICS  OF  EXISTING  GLACIERS 

depression  is  deepened,  and,  if  upon  a  steep  slope,  its  wall 
becomes  recessed  (see  Fig.  7). 

The  occupation  of  a  V-shaped  valley  by  snow,  as  Matthes 
has  further  shown,  tends  through  the  operation  of  this 
process  to  transform  it  into  one  of  U -sect ion,  since  the  weath- 
ered rock  material  upon  the  slopes  is  transported  by  the  rills 
and  deposited  upon  the  floor.  All  gradations  from  nivated 
to  glaciated  forms  are  to  be  found  in  the  Bighorn  range. 

During  the  field  season  of  1909  the  writer  took  the  oppor- 
tunity to  examine  neve  regions  and  high-level  snowbanks  in  a 
number  of  districts,  with  the  result  of  confirming  the  im- 
portance of  the  nivation  process  as  outlined  by  Matthes. 
In  plate  2  A  and  B  are  shown  two  snowbanks  which  were 
photographed  on  July  25  near  the  summit  of  Quadrant 
mountain,  in  the  Gallatin  range  of  the  Yellowstone  National 
Park.  The  gently  sloping  surface  of  this  mountain  repre- 
sents the  pre-glacial  upland  unmodified  by  Pleistocene  gla- 
ciation.  Though  between  9000  and  10,000  feet  above  sea,  it 
supports  a  rich  herbage,  and  is  a  favorite  grazing-ground  of 
the  elk.  In  A  of  plate  2  the  snow  bank  is  seen  surrounded 
by  a  wide  zone  within  which  no  grass  is  growing,  but  where  a 
finely  comminuted  brown  soil  is  becoming  a  prey  to  the  mov- 
ing water.  B  of  plate  2  exhibits  another  bank  lying  in  the 
depression  which  it  has  largely  hollowed.  At  its  lower  end 
(at  the  left)  is  seen  an  apron  of  fine  brown  mud  deposited  by 
the  overburdened  stream  as  it  issues  from  beneath  the 
drift. 

Later  the  writer  has  had  in  Swedish  Lapland  opportunity 
to  observe  the  results  of  the  nivation  process  under  excep- 
tionally favorable  circumstances.  Here  in  place  of  a  pre- 
glacial  surface,  such  as  has  been  dissected  in  the  American 
mountain  districts  already  described,  the  surface  of  the 
country  has  been  planed  down  to  softly  rounded  knobs  of 
rather  large  scale  under  the  influence  of  the  mantling  con- 


PLATE  2. 


A.    Summer  snowbank  surrounded  by  brown  border  of  finely  comminuted  rock. 
Quadrant   Mountain,  Y.N.P. 


B.    Snowbank  lying  in  a  depression  largely  of  its  own  construction.     Note  stream, 
outwash  of  fine  mud  at  the  left.     Quadrant  Mountain,  Y.N.P. 


THE   CIRQUE  AND  ITS   RECESSION 


21 


tinental  glacier  of  Pleistocene  time.  Subsequent  to  this  gen- 
eral planation  the  higher  areas  have  in  favorable  situations 
been  occupied  either  by  mountain  glaciers  or  by  more  or  less 
persistent  snow-drifts.  The  drift  sites  are  found  upon  the 
hillsides  as  distinct  niches  in  which  the  characteristic  "  arm- 
chair "  form  of  the  incipient  cirque  is  already  apparent.  It  is 
the  scale  particularly  which  distinguishes  them  from  glacial 
amphitheatres  (see  Fig.  8).  It  is  of  great  interest  to  find 


FIG.  8. — The  characteristic  form  of  drift  sites  on  hillsides  in  Swedish  Lapland. 
The  form  of  the  cirque  is  already  discernible.  On  the  floor  a  division  into  hexa- 
gons indicates  that  the  process  of  solifluction  has  played  an  important  part.  (After 
a  photograph  by  G.  W.  v.  Zahn.)26 

that  the  quite  remarkable  but  as  yet  little  understood  pro- 
cess of  rock  flow  (solifluction)  has  here  played  an  impor- 
tant part  in  shaping  the  incipient  cirque.  The  floors  of  the 
drift  sites  are  in  some  instances  at  least  divided  into  the 
hexagonal  pattern  so  characteristic  of  soil  flow  on  relatively 


22          CHARACTERISTICS  OF  EXISTING  GLACIERS 

flat  surfaces.26  Inasmuch  as  it  is  now  recognized  that  melt- 
ing snow  is  the  immediate  requisite  for  effective  solifluction, 
it  is  apparent  that  this  process  in  some  of  its  phases  at  least 
is  clearly  allied  to  the  process  of  nivation. 

An  interesting  question  is  at  what  point  the  snow-field  or 
neve  will,  by  taking  on  a  motion  of  translation,  assume  the 
functions  of  a  glacier.  At  this  stage  of  transition  the  Berg- 
schrund  should  first  make  its  appearance.  Comparison  of 
nivated  and  glaciated  slopes  in  the  Bighorn  mountains  led 
Matthes  to  think  that  upon  a  12  per  cent,  grade  the  neve 
must  attain  a  thickness  of  at  least  125  feet  before  motion  is 
possible.  Another  possible  method  of  approaching  this 
problem  has  suggested  itself  to  the  writer.  In  mountains 
like  the  Selkirks,  with  steep  slopes  terraced  by  the  flatly  dip- 
ping layers  in  the  rock,  a  peculiar  type  of  small  cliff  glacier 
is  nourished  high  above  the  larger  snow-fields  of  the  range 
and  avalanched  upon  the  lower  shelves  so  as  to  leave  vertical 
sections  open  to  study  (see  plate  3  A).  Perhaps  because  of 
their  small  size  these  cliff  glaciers  have  not  developed  cirques, 
though  a  Bergschrund  parallels  the  generally  straight  head- 
wall.  Examined  through  a  powerful  glass,  the  snow  in  the 
lower  layers  can  be  seen  to  have  lost  its  brilliant  whiteness, 
though  it  does  not  yet  appear  as  ice.  A  number  were  ex- 
amined with  a  view  to  determine  the  approximate  minimum 
thickness  of  the  glacier,  but  all  exceed  the  minimum  estimate 
of  Matthes  by  at  least  100  feet.  This  is  not  regarded  as  in 
any  way  discrediting  his  figure,  but  rather  as  suggesting  the 
possibility  of  more  thorough  examination  along  the  same 
line. 

REFERENCES 

1  "Geology,"  vol.  1 :  "Processes  and  their  Results,"  1904,  pp.  272-276, 
and  especially  fig.  250.     See  also  "College  Geology,"  by  the  same  authors, 
1909,  p.  256. 

2  John  Tyndall,  "On  the  Conformation  of  the  Alps,"  Phil.  Mag.,  Ser. 
4,  vol.  24,  1862,  pp.  169-173. 


THE  CIRQUE  AND  ITS  RECESSION  23 

*  T.  G.  Bonney,  "On  the  Formation  of  'Cirques,'  with  their  Bearing 
upon  Theories  attributing  the  Excavation  of  Mountain  Valleys  mainly 
to  the  Action  of  Glaciers,"  Quart.  Jour.  Geol.  Soc.,  vol.  27,  1871,  pp.  312- 
324. 

4B.  Gastaldi,  "On  the  Effects  of  Glacier-erosion  in  Alpine  Valleys," 
ibid.,  vol.  29,  1873,  pp.  396-401. 

6Amund  Helland,  "Ueber  die  Vergletscherung  der  Faroer,  sowie  der 
Shetland  und  Orkney  Inseln,"  Zeitsch.  d.  Deutsch.  Geol.  Gesellsch.,  vol.  31, 
1878,  pp.  716-755,  especially  pp.  731-733. 

6 1.  C.  Russell,  "Quarternary  History  of  Mono  Valley,  California," 
8th  Ann.  Rept.  U.  S.  Geol.  Surv.,  1889,  pp.  352-355. 

7  A.  R.  Wallace,  "The  Ice  Age  and  its  Work,"  Fortnightly  Review,  vol. 
60,  1893,  especially  p.  757. 

8E.  de  Martonne,  "Sur  la  periode  glaciaire  dans  les  Karpates  meri- 
dionales,"  C.  R.  Acad.  Sci.  Paris,  vol.  129,  1899,  pp.  894-897 ;  ibid.,  vol. 
132,  1901,  p.  362. 

9  Albrecht  Penck,  "Morphologic  der  Erdoberflache,"  vol.  2,  1894,  pp. 
307-308,  figs.  17-20. 

10  E.    Richter,    "  Geomorphologische   Beobachtungen   aus   Norwegen," 
Sitzungsber.   Wiener  Akad.,   Math.-Naturw.  KL,  vol.  106,   1896,  Abt.  I., 
pp.  152-164,  2  pis.  and  2  figs. 

11  See  topographic  definition  of  the  cirque  by  De  Martonne  ("La  periode 
glaciaire  dans  les  Karpates  meridionales,"   C.R.,  9e  Cong.  Geol.  Intern., 
Vienna,  1903,  pp.  694,  695). 

12  E.  Richter,  "Geomorphologische  Untersuchungen  in  den  Hochalpen," 
Pet.  Mitt.,  Erganzungsheft  132,  1900,  pp.  1-103,  pis.  1-6. 

13  "Scenery  of  Scotland,"  p.  183  (revised  in  1901). 

14  H.  Reusch,  Norges  Geol  giske  Undersogelse,  No.  32,  Aarbog  for  1900, 
1901,  pp.  259,  260. 

15  "Alpine  Valleys  in  Relation  to  Glaciers,"  Quart.  Jour.  Geol.  Soc.,  vol. 
68,  1902,  p.  699. 

16  "The  effect  is  precisely  like  a  waterfall.     The  falling  snow  and  ice 
dig  a  hollow  depression  at  the  foot  of  the  steep  descent  just  as  water  does." 
(Nat.  Geogr.  Mag.,  vol.  9,  1898,  p.  419.) 

17  W.  D.  Johnson,  "An  Unrecognized  Process  in  Glacial  Erosion"  (read 
before  the  Eleventh  Annual  Meeting  of  the  Geological  Society  of  America), 
Science,  N.S.,  vol.  9,  1899,  p.  106;   also  "The  Work  of  Glaciers  in  High 
Mountains"  (lecture  before  the  National  Geographic  Society),  ibid.,  pp. 
112,  113.     The  first  public  formulation  of  the  doctrine  by  Mr.  Johnson 
was  in  an  address  before  the  Geological  Section  of  the  Science  Associa- 
tion of  the  University  of  California,  delivered  September  27,  1892. 

18  W.  D.  Johnson,  "  Maturity  in  Alpine  Glacial  Erosion,"  Jour.  Geol., 
vol.  12,  1904,  pp.  569-578  (read  at  Intern.  Congr.  Arts  and  Sciences,  St. 
Louis,  1904). 

19 1.  C.  Russell,  "Glaciers  of  North  America,"  1897,  p.  193. 

20  G.  K.  Gilbert,  "Systematic  Asymmetry  of  Crest-lines  in  the  High 
Sierras  of  California,"  Jour.  Geol.,  vol.  13,  1905,  pp.  579-588.  See  also 
E.  C.  Andrews,  ibid.,  vol.  14,  1906,  p.  44. 


24  CHARACTERISTICS  OF  EXISTING  GLACIERS 

21  Many  European  glacialists  and  among    them  apparently  Garwood 
(Geogr.  Jour.,  vol.  36,  1910,  p.  313),  have  failed  clearly  to   understand 
that  the  basal  sapping  occurs  at  and  near  the  base  of  the  Bergschrund. 

22  Albrecht  Penck,  "Glacial  Features  in  the  Surface  of  the  Alps,"  Jour. 
Geol.,  vol.  13,  1905,  pp.  15-17. 

23  Francois  E.  Matthes,  "Glacial  Sculpture  of  the  Bighorn  Mountains, 
Wyoming,"  21st  Ann.  Rept.  U.  S.  Geol.  Surv.,  1899-1900,  pp.  167-190. 

24  Mainly  in  later  seasons. 

25  The  structure  of  the  pavement  in  the  foreground  has  been  added  from 
another  photograph. 

26  See  H.  W.  Feilden,  "Notes  on  the  Glacial  Geology  of  Arctic  Europe 
and  its  Islands,"  Quart.  Jour.  Geol.  Soc.,  vol.  62,  1896,  p.  738 ;  also  O. 
Nordenskiold,  "On  the  Geology  and  Physical  Geography  of  East-Green- 
land," Meddelelser  om  Gronland,  vol.  28,  1908,  p.  273;  also  O.  Nordenskiold, 
*'Die  Polarwelt  und  ihre  Nachbarlander,"  Leipzig  and  Berlin,  1909,  p.  63  ; 
also  W.  H.  Hobbs,  "Soil  Stripes  in  Cold  Humid  Regions,"  12th  Report 
Mich.  Acad.  Sci.,  1910,  pp.  51-53. 


CHAPTER  II 

HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND 

The  Upland1  dissected. — Having  obtained  a  clear  concep- 
tion of  the  process  of  head-wall  erosion  through  basal  sap- 
ping, Johnson  was  in  a  position  to  account  for  the  topography 
which  he  encountered  in  the  High  Sierras  of  California.  This 
topography  is  best  described  in  his  own  words : 2  — 

In  ground  plan  the  canyon  heads  crowded  upon  the  summit 
upland,  frequently  intersecting.  They  scalloped  its  borders, 
producing  remnantal  table  effects.  In  plan  as  in  profile,  the 
inset  arcs  of  the  amphitheatres  were  vigorously  suggestive  of 
basal  sapping  and  recession.  The  summit  upland  —  the  pre- 
glacial  upland  beyond  a  doubt  —  was  recognizable  only  in 
patches,  long  and  narrow  and  irregular  in  plan,  detached  and 
variously  disposed  as  to  orientation,  but  always  in  sharp  tabu- 
lar relief  and  always  scalloped.  I  likened  it  then,  and  by  way 
of  illustration  I  can  best  do  so  now,  to  the  irregular  remnants 
of  a  sheet  of  dough  on  the  biscuit  board  after  the  biscuit  tin 
has  done  its  work. 

In  a  portion  of  the  region  where  Johnson's  studies  were 
made,  his  views  have  received  verification  by  Lawson  in  a 
beautifully  illustrated  paper.3  Davis  has  furnished  an  ex- 
cellent example  from  the  Tian  Shan  mountains  of  the  opera- 
tion of  the  same  cirque-cutting  process,  recording  his  adhe- 
sion to  the  Johnson  doctrine,4  though  many  of  his  later  papers 
would  indicate  that  he  did  not  ascribe  large  importance  to 

25 


26  CHARACTERISTICS  OF  EXISTING  GLACIERS 


the  discovery.5     In  1909  two  papers  from  his  pen  give,  how- 
ever, larger  prominence  to  the  process.6 

With  little  doubt  the  failure  to  generally  recognize  the  im- 
portance of  this  process  of  cirque  recession,  clearly  here  a 
more  effective  agent  than  abrasion,  is  to  be  explained  by  the 

fact  that  in  parts  of 
Europe  and  in  the 
Alps  in  particular, 
one  looks  in  vain  for 
evidences  of  the  ear- 
lier and  more  signifi- 
cant stages  of  the 
process.  Glaciation 
was  here  so  vigorous 
as  to  cause  the  re- 
moval of  all  summit 
upland.  Within  the 
arid  regions  of  the 
western  United 
States,  a  more  fruit- 
ful field  for  study  is 
to  be  found.  Here  the  work  of  Johnson  has  been  supple- 
mented by  that  of  Gilbert7  and  Matthes.8  Perhaps  no- 
where are  the  early  stages  of  the  process  so  clearly  revealed 
as  in  the  Bighorn  Mountains  of  Wyoming  (see  Fig.  9). 

A  somewhat  more  advanced  stage  of  the  same  process  is  to 
be  found  in  the  Uinta  mountains  of  Wyoming,  recently  de- 
scribed in  a  valuable  monograph  by  Atwood,  though  here 
without  consideration  of  the  cirque-cutting  process  in  ac- 
counting for  the  present  topography.9  Yet  nowhere,  so  far 
as  the  present  writer  is  aware,  has  a  view  been  reproduced 
which  so  well  illustrates  the  remnantal  tableland  and  the 
"biscuit-cutting"  process  of  cirque  recession  (see  Fig.  10).10 
The  present  writer  has  photographed  other  examples  of  the 


FIG.  9.  —  Pre-glacial  upland  invaded  by  cirques  — 
"biscuit-cutting"  effect;  Bighorn  Mountains, 
Wyoming. 


PLATE  3. 


A.    View  of  the  Yoho  Glacier  at  the  head  of  the  Yoho  Valley,  showing  to  the  right 
a  series  of  three  small  cliff  glaciers.     Canadian  Rockies. 


B.    Pre-glacial   upland   on  Quadrant    Mountain,  Y.N.P.,   invaded   by  the  cirque 
known  as  the  "Pocket." 


HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND         27 

same  type  in  the  Yellowstone  National  Park  (see  plate  3  B 
and  Fig.  11).    Remnants  of  the  pre-glacial  surface  will,  in 


FIG.  10.  —  View  of  the  scalloped  tableland  within  the  Uinta  range  and  near  the 
head  of  the  west  fork  of  Sheep  Creek  (after  Atwood). 

any  given  district,  be  large  or  small  according  as  nourishment 
of  the  glaciers  has  been  insufficient  or  the  reverse.  The 
Uinta  range,  which  extends  in  an  east-west  direction,  and, 


FIG.  11.  —  Map  of  Quadrant  Mountain,  a  remnant  of  the  pre-glacial  upland  on 
the  flanks  of  the  Gallatin  Range,  Y.  N.  P. 


28 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


like  the  Bighorn  mountains,  has  a  core  of  homogeneous 
granitic  rock,  displays  this  fact.  An  examination  of  At- 
wood's  map  n  shows  that  to  the  eastward,  where  the  precipi- 
tation has  been  least,  the  remnants  of  the  original  upland  are 
more  considerable.  This  qualifying  condition  of  glacier 
nourishment  will  be  subject  to  some  modification  because  of 
peculiarities  in  snow  distribution.  As  shown  by  Gilbert,  the 


FIG.  12.  —  Series  of  semicircular  glacial  amphitheatres  whose  scalloped  crest  forma 
part  of  the  divide  of  the  North  American  continent. 

first  glaciers  within  any  mountain  district  will  probably 
appear  upon  that  side  of  the  divide  which  is  in  the  lee  of  the 
prevailing  winds.  This  fact  is  particularly  well  brought  out 
in  Fig.  12. 

Such  a  condition  as  is  here  represented,  gives  a  most  de- 
cisive answer  to  the  question  concerning  the  protective  or 
denuding  action  of  glacier  ice.  To  the  west  of  the  divide 
the  snow  has  been  swept  clear,  and  these  sweepings  lodg- 
ing in  the  lee  have  produced  the  glaciers  on  this  side  only. 


PLATE  4. 


K 


g 


*| 

^ 
|1 

«a 

IS 


I 


H 
ii 


2    M    S    C8 

'C     e   J2    W) 

2  'S   o   c 

fi«-l 

I5I& 

nil 

s!fl 

'^3  *0  T3   "S 


^    S    >, 

•all 


§   II 


c  ^  -c  a 

O 


1-1    <N    00    T* 


PLATE  5. 


Multiple  secondary  cirques  on  the  west  face  of  the  Wannehorn  seen 

across  the  Great  Aletsch  Glacier,  to  which  it  is  tributary. 

(After  a  photograph  by  I.  D.  Scott.) 


HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND         29 

While  this  glacial  cover  has  no  doubt  protected  its  base  from 
the  ordinary  weathering  process,  the  extraordinary  weather- 
ing in  the  Bergschrund  combined  with  abrasion  and  plucking 
upon  the  floor,  has  excavated  some  2000  feet  of  rock  material, 
even  if  we  were  to  assume  that  the  "  unprotected  "  surface 
to  the  westward  has  not  been  lowered. 

The  cwms  of  Wales  have  not  as  yet  entirely  removed  the 
summit  upland  in  which  they  have  been  recessed,  and  this 
residual  surface  perhaps  furnishes  the  best  European  example 
of  an  earlier  stage  in  the  process  of  cirque  recession.12 

Modification  in  the  Plan  of  the  Cirque  as  Maturity  is  Ap- 
proached. —  Owing  to  the  fact  that  the  sapping  process 
within  the  cirque  operates  on  all  sides,  its  early  plan,  when 
the  upland  surface  is  supplying  snow  from  all  directions,  will 
approach  the  circle  (see  Fig.  9  and  plate  3  B).  Moreover, 
in  this  stage  the  cirque  will  be  but  little,  if  any,  wider  than 
the  deepened  and  widened  valley  below  (see  plate  4,  Figs.  1 
and  2).  Later,  with  the  continuation  of  the  sapping  process, 
the  cirque  becomes  enlarged  to  such  an  extent  that  its  sides 
form  recesses  in  the  walls  of  the  valley.  Thus,  in  the  plan, 
the  glacial  valley  of  this  stage  bears  some  resemblance  to  that 
of  a  nail  with  a  large  rounded  head. 

As  the  upland  is  still  further  dissected,  the  cirque  becomes 
more  irregular  in  outline  and  widens  into  a  roughly  elliptical 
form,  not  infrequently  allowing  it  to  be  seen  that  it  is  in 
reality  composite  or  made  up  of  several  cirques  of  a  lower 
order  of  magnitude  (plate  5,  plate  6  B  and  Fig.  13). 

Grooved  and  Fretted  Uplands. --The  new  emphasis  put 
upon  topographic  expression  of  character  in  the  maps  issued 
by  government  bureaus  during  the  past  few  years,  has  fur- 
nished physiographers  a  tool  of  which  they  are  hardly  yet 
fully  aware.  Before,  the  aim  of  topographers  seemed  to  be 
to  suppress  all  character  through  a  rounding  off  of  angles  and 
an  averaging  of  the  data.  Perhaps  nowhere  has  the  change 


30          CHARACTERISTICS  OF  EXISTING  GLACIERS 

been  more  noteworthy  than  in  the  maps  issued  by  the 
United  States  Geological  Survey,13  and  the  later  sheets  par- 
ticularly, when  relating  to  glaciated  mountain  districts, 
afford  us  the  opportunity  of  tracing  the  successive  steps  in  the 
dissection  of  such  upland  districts  by  the  cirques  of  moun- 
tain glaciers.  For  plate  4,  four  areas  have  been  selected  to 
represent  successive  stages  in  such  a  progressive  dissection. 
An  early  product,  in  which  large  remnants  of  the  upland  sur- 
face still  remain,  may  well  be  designated  a  "  grooved  or  chan- 
nelled "  upland  (see  plate  6  A  a). 

As  the  hemicycle  advances,  it  will  be  observed  that  on  the 
flanks  of  the  range  are  found  the  largest  remnants  of  the 
original  upland  surface  (see  Fig.  II),14  owing  to  the  tendency 
of  the  cirque  to  push  its  side  walls  out  beyond  the  limits  of 
the  U-shaped  valley  below.  With  complete  dissection  of  the 
plateau  no  tabular  remnants  are  to  be  discovered.  The  gen- 
eral level  of  the  district  has  now  been  lowered,  but  above  this 
irregular  surface  project  one  or  more  narrow  pinnacled 
ridges  —  files  of  "  gendarmes  "  —  separated  by  crevices  or 
"  chimneys."  These  palisades  at  fairly  regular  intervals 
throw  off  lateral  palisades  having  crests  which  fall  away  in 
altitude  as  they  recede  from  the  trunk  ridge.  In  general 
terms,  and  describing  the  major  features  only,  we  have  here 
to  do  with  a  gently  domed  surface,  on  which  is  a  fretwork 
of  comb-like  ridges  projecting  above  it.  This  surface  may 
be  designated  a  "  fretted  upland  "  (see  plate  6  A  6).  Such  a 
condition  is  realized  in  the  Alps,  and  is  seen  to  special  ad- 
vantage from  the  summit  of  Mont  Blanc  (see  plate  7  A). 

The  transition  from  the  grooved  to  the  fretted  upland  is 
well  brought  out  in  two  views  taken  by  Lawson  in  the  High 
Sierras  of  California  (loc.  cit.,  plate  45,  A  and  B).  The 
fretted  upland  differs  from  the  grooved  upland  of  an  earlier 
stage  of  the  cycle  in  the  complete  dissection  of  the  surface. 
The  character  of  the  fretted  surface  is  well  brought  out  by 


PLATE  6. 


A.    (a)  A  grooved  upland  in  the  Bighorn  Mountains,  Wyoming.     (6)  A  fretted  up- 
land, Alaska. 


B.  Multiple  cirque  of  the  Dawson  glacier,  having  a  major  subdivision  into  halves, 
which  enclose,  respectively,  the  Dawson  and  the  Donkin  neves.  The  view  is  from 
the  Asulkan  Pass,  Selkirk  Mountains. 


PLATE  7. 





A.  Fretted  upland  of  the  Alps  as  seen  looking  northeastward  from  the  summit  of 
Mont  Blanc,  July  25,  1908.  The  cirque  to  the  left  is  that  of  the  Glacier  de 
Talefre,  with  the  Jardin  in  its  centre,  and  distant  about  10  miles. 


B.    Map  of  a  portion  of  one  of  the  Lofoten  Islands,  showing  a  fretted  surface  par- 
tially submerged  and  emphasizing  the  approximate  accordance  of  summit  levels. 


HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND         31 

the  topography  of  the  Lofoten  Islands  off  the  arctic  coast  of 
Norway,  where  the  effect  is  somewhat  heightened  through 
the  partial  submergence  and  consequent  obliteration  of  the 
irregularities  in  the  floor  (see  plate  7  B). 

At  this  stage  there  is  undoubtedly  a  general  accordance 
of  level  in  the  crests  of  the  frets  upon  the  domed  surface,  as 
Daly,  taking  due  account  of  the  cirque-cutting  process,  has 
claimed.15  Moreover,  the  existence  of  such  a  series  of  frets 
as  are  to  be  found  in  the  Alps,  forces  us  to  conclude  that  such 
an  accordance  of  summits  persists  for  a  considerable  time. 
Were  this  not  the  case,  we  should  find  a  larger  number  of  low 


n 

FIG.  13.  —  Diagram  to  illustrate  the  manner  of  dissection  of  an  upland  by  mountain 

glaciers. 

cols  and  a  longer  persistence  of  the  semicircular  form  of  the 
cirque.  It  seems  probable,  therefore,  that  a  very  definite 
relationship  obtains  between  the  plan  of  the  cirque  and  that 
of  the  near-lying  upland  remnants  that  contribute  snow  to  its 
basin.  So  soon  as  cirques  approach  from  opposite  sides  of  a 
divide,  the  portions  of  their  basins  which  are  more  nearly  ad- 
jacent receive  less  snow,  and,  in  consequence,  accomplish  less 
sapping  than  the  walls  on  either  side  where  snow  is  lodged  in 


32  CHARACTERISTICS  OF  EXISTING  GLACIERS 

a  quantity  but  slightly  diminished.  This  self-regulating 
process  will  tend  to  broaden  the  cirque  and  eventually  give  it 
irregularities  of  outline  dependent  primarily  upon  the  initial 
positions  and  the  individual  nourishments  of  its  near-lying 
neighbours. 

Characteristic  higher  Relief  Forms  of  the  Fretted  Upland.  — 
In  the  earlier  stages  of  mountain  glaciation  the  upland  is  chan- 
nelled by  valleys  U-shaped  in  their  upper  stretches,  and  some- 
what broadened  into  steep-walled  amphitheatres  at  their 
heads.  With  the  complete  dissection  of  the  upland,  the  coa- 
lescence of  the  many  cirques  at  last  cuts  away  every  remnant 
of  the  original  surface  and  yields  relief-forms  which  are  de- 
pendent mainly,  as  already  stated,  upon  the  initial  positions 
of  the  cirques.16 

If  there  be  a  highest  area  within  the  upland,  the  snow  will 
be  carried  farthest  from  it  by  the  wind,  and  this  will  be  in  con- 
sequence the  last  to  succumb  to  the  cirque-cutting  process. 
The  dome  of  Mont  Blanc  in  the  midst  of  a  forest  of  pinnacles, 
no  doubt  owes  its  peculiar  form  to  the  fact  that  it  dominated 
the  pre-glacial  upland. 

A  high  district  whose  area  is  not  too  large  compared  with 
that  of  the  individual  cirques,  when  at  last  dissected  by  the 
cirques  may  be  designated  a  "  karling." 17  A  typical  example 
from  Northern  Wales  is  represented  in  plate  8. 

Elsewhere  within  the  upland  the  coalescence  of  cirques  has 
produced  comb-like  palisades  of  sharp  rock-needles  which 
have  long  constituted  the  aiguille  type  of  mountain  ridge.  In 
the  literature  of  physiography,  such  ridges  have  perhaps  most 
frequently  been  designated  by  the  term  "arete"  (fishbone), 
though  in  the  Alps  the  term  "  grat " 18  (edge)  has  been  applied 
especially  to  the  smaller  and  lateral  ridges  of  this  type.  I  pro- 
pose to  use  for  all  such  palisades  of  needles  derived  by  this 
process  the  name  "  comb-ridge ;;19  as  the  best  English  term 
available.  The  frequent  occurrence  of  lateral  arms  joined 


PLATE  8. 


A  karling  in  North  Wales  (from  the  Bangor  sheet  of  the  British  Ordnance  Survey, 

1907). 


HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND       33 


to  the  main  palisade  of  needles  suggests  a  differentiation  into 
main  and  lateral  comb-ridges. 

In  every  mountain  district  maturely  dissected  by  glaciers, 
are  to  be  found  sharp  horns  of  larger  base  and  especially  of 
higher  altitude  than  the  individual  minaret-like  teeth  of  the 
comb-ridges.  They  are  further  in  contrast  with  the  latter 
by  having  an  approximately  pyramidal  form,  and  a  base 
most  frequent- 
ly a  triangle 
with  flatly  in- 
curving sides. 
They  appear 
most  frequent- 
ly at  the  junc- 
tion points  of 
the  comb-ridges 
between  three 
or  more  impor- 
tant snow-fields 
(see  Fig.  14). 
Such  forms  are 
generally  termed  "  horns  "  in  the  Alps,  and  the  word  being 
of  the  same  form  in  English,  it  may  well  be  retained  as  a 
technical  expression.  The  Matterhorn  in  Switzerland  is  the 
type  par  excellence  (see  plate  9  A),  though  similar  and 
almost  equally  striking  examples  are  numerous  ;  as,  for 
example,  the  Weisshorn  and  Gross  Glockner  in  the  Alps, 
Mount  Assiniboine  in  the  Canadian  Rockies,  or  Mount  Sir 
Donald  in  the  Selkirks.  The  triangular  base  and  pyramidal 
form  are  so  common  to  this  feature  that  they  have  found 
expression  in  the  local  names,  as  Dreieckhorn,  Delta-form 
peak,  etc. 

The  Col  and  its  Significance.  --The  prominent  horns  of  any 
glaciated  mountain  district  no  doubt  occupy  positions  cor- 


FIG.  14.  —  Position  of  the  Aletsch-  and  Dreieckhorns  be- 
tween the  Upper,  Middle,  and  Great  Aletsch  neves. 


34 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


responding  in  the  main  to  the  more  elevated  areas  in  the 
original  upland  surface,  since  such  positions  would  be  earliest 
cleared  of  snow,  and  hence  latest  attacked  by  the  cirques. 
After  complete  dissection  of  the  upland,  the  comb-ridges 
which  fret  its  surface  will  be  attacked  from  opposite  sides, 
and  their  crests  will  be  first  lowered  at  the  points  of  tan- 
gency  of  the  adjacent  cirques  —  generally  near  the  middle 

points  of  their  curving 
outlines.  The  sky-line  of 
the  ridge  will  thus  be 
lowered  in  a  beautiful 
curve  forming  a  pass  or 
col.  Inasmuch  as  the 
cirque  approaches  in  its 
form  an  inverted  and 
truncated  cone  of  acumi- 
nated type,  the  curve  to 
which  the  rim  of  the  col 
approximates  will  be  fur- 
nished by  the  intersection 
of  two  cones  of  revolution 
with  the  same  apical  angle 
and  having  parallel  axes 
(see  Fig.  15  and  plate  9 
B).  This  curve  is  approx- 
imately a  hyperbola,  the 
eccentricity  of  which  will  be  largely  dependent  upon  the 
relative  sizes  of  the  cirques  in  question. 

The  corries  of  the  Scottish  Highlands,  being  generally  of 
small  size,  have  coalesced  to  produce  a  very  characteristic 
scalloping  of  the  horizon  line  seen  to  advantage  in  Ben  Nevis, 
or,  better  still,  in  the  sculptured  gabbro  of  the  Cuchulin  hills 
in  Skye.20  To  judge  from  views,  also,  such  forms  are  found 
in  North  Wales,  features  which  in  many  respects  are  different 


FIG.  15.  —  Diagram  to  illustrate  the  forma- 
tion of  a  col  through  the  intersection  of 
cirques. 


PLATE  9. 


A.    View  of  the  Matterhorn  from  the  Corner  Grat. 
(After  a  photograph  by  I.  D.  Scott.) 


B.    Col  between  Mt.  Sir  Donald  and  Yogo  Peak  in  the  Selkirks, 
showing  the  characteristic  hyperbolic  profile. 

(Copyright  by  the  Keystone  View  Company.) 


HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND        35 

from  those  found  in  the  Alps  or  in  the  North  American 
mountains.21 

It  must  be  regarded  as  of  deep  significance  that  mountain 
passes  in  areas  which  have  supported  glaciers  are  so  generally 
at  high  levels.  Deep  glacier-cut  valleys  available  as  high- 
ways and  transecting  high  ranges  are  extremely  rare;  so  far 
as  the  writer  is  aware,  being  known  only  from  the  Southern 
Andes22  and  Alaska.23  This  fact  must  have  its  explanation, 
it  is  believed,  in  a  notable  and  abrupt  retardation  in  the  rate 
of  cirque-wall  recession,  following  close  upon  the  dissection 
of  the  upland.  Whether  this  is  due  to  the  reduced  snow 
accumulation  immediately  beneath  the  cirque  wall  owing 
to  the  lack  of  a  near-lying  collecting  ground,  it  is  as  yet  too 
early  to  say;  but  a  comparison  of  the  acclivities  in  the 
marginal  snow-slopes  on  neves  of  the  Bighorn  and  Alaskan 
districts  might  yield  an  answer  to  the  question. 

Though  the  sapping  process  at  the  base  of  cirque  walls 
up  to  maturity  is  doubtless  far  more  potent  than  abrasion 
and  plucking  upon  the  floor  of  the  amphitheatre,  it  seems 
likely  that  in  the  subsequent  stage  the  reverse  is  the  case. 
This  would  at  least  explain  the  tendency  of  glacier  valleys 
to  deepen  rapidly  in  the  higher  altitudes,  or,  in  Johnson's 
phrase,  to  get  "  down  at  the  heel:" 

The  Advancing  Hemicycle. -- With  the  augmentation  of 
rigorous  climatic  conditions  within  any  district  where  glaciers 
already  exist,  the  latter  will  be  continually  more  amply 
nourished,  and  must  in  consequence  increase  steadily  in  size. 
Such  climatic  changes  may  even  be  conceived  so  considerable 
that  at  last  the  entire  range  is  submerged  beneath  snow 
and  ice,  thus  producing  an  ice-cap. 

Direct  observation  of  the  successive  stages  through  which 
glaciers  pass  from  their  initiation  to  their  culmination  in  an 
ice-cap,  is,  of  course,  impossible,  for  the  reason  that  we  live 
in  a  receding  hemicycle  in  which  practically  all  known  gla- 


36  CHARACTERISTICS  OF  EXISTING  GLACIERS 

ciers,  instead  of  expanding,  are  drawing  in  their  margins; 
yet  a  synthetical  reconstruction  of  the  life-history  is  none 
the  less  possible.  To  employ  an  illustration  already  used  in 
a  different  connection,  in  order  to  learn  the  life-history  of  a 
particular  species  of  forest  tree,  it  would  not  be  necessary 
to  sit  down  and  observe  an  individual  tree  from  the  germina- 
tion of  its  seed  to  the  decadence  of  the  full-grown  tree.  We 
may  with  equal  profit  go  into  the  forest  and  observe  trees 
of  the  same  species  in  all  stages  of  development.  In  the 
study  of  glaciers  our  opportunity  is  hardly  so  fortunate 
as  this,  for,  as  already  stated,  all  glaciers  appear  to  be  in  the 
declining  stage  (if  we  ignore  the  short  period  variations) 
whereas  it  is  the  advancing  hemicycle  with  which  we  are  now 
concerned.  The  characters  of  glaciers  as  concerns  their  size 
and  shape  depend,  however,  in  so  large  a  measure  upon  the 
one  element  of  alimentation,  that  if  we  neglect  characters  of 
a  second  order  of  magnitude,  we  may  by  inference  construct 
the  history  with  sufficient  accuracy  from  existing  examples. 
The  alimentation  of  mountain  glaciers  is  dependent  upon 
the  amount  of  precipitation  and  upon  the  temperature,  the 
former  being  in  large  measure  determined  by  the  adapta- 
bility of  the  relief  for  local  adiabatic24  and  contact  refrigera- 
tion of  the  air.  The  important  factor,  temperature,  while 
a  function  of  many  variables,  yet  in  a  broad  way  varies  di- 
rectly with  latitude  and  altitude.  The  size  and  the  form 
of  glaciers  is,  however,  determined,  not  solely  by  nourish- 
ment (mainly  in  the  higher  levels),  but  also  to  some  extent 
by  losses  (particularly  in  the  lower  levels).  In  the  main, 
however,  the  losses  are  controlled  by  the  same  factors  as  the 
gains,  and  maintain  to  them  a  more  or  less  determinate  pro- 
portional relationship.  Exceptions  to  this  definite  proportion 
occur  when  in  high  latitudes  the  glacier  is  attacked  directly 
by  the  sea  (tidewater  glaciers),  when  it  is  suddenly  melted 
by  the  heat  of  a  volcanic  eruption  (Icelandic  Jokulls),  or 


HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND         37 

when  disturbed  by  a  heavy  earthquake  (Muir  glacier  in  1899). 
In  form  glaciers  will  be  in  large  measure  determined  by  the 
existing  topography  of  the  upland,  which  may  generally 
be  assumed  to  be  some  product  of  sub-aerial  erosion.  *  Start- 
ing, therefore,  with  the  puny  glaciers  of  arid  regions  in  low 
latitudes,  and  ending  with  the  high  latitude  glaciers  within 
areas  of  excessive  precipitation,  we  run  almost  the  whole 
gamut  of  glacier  alimentation. 

The  initial  forms  of  glaciers  may  be  described  as  snow- 
bank, "new-born,"  or  nivation  glaciers,  and  will  at  first 
be  few  in  number  and  located  with  wide  intervening  spaces 
of  upland.  The  continuance  of  the  nivation  process  will 
deepen  other  intermediate  small  depressions  upon  the  upland, 
so  that  with  increasing  snowfall  additional  glaciers  will 
appear  in  the  spaces  between  the  first  as  the  latter  are  devel- 
oping their  amphitheatres.  These  cirques,  at  first  no  wider 
than  the  valleys  below,  will  later  cut  recesses  on  either  side, 
at  the  same  time  that  the  glacier  is  pushed  farther  down  the 
valley  and  occupies  its  bed  to  a  greater  and  greater  depth. 
The  grooved  upland  of  this  stage,  through  additional  cirque 
recession  in  the  highlands  and  through  abrasion  and  plucking 
in  the  intermediate  levels,  becomes  at  last  transformed  into 
the  fretted  upland,  with  its  network  of  projecting  comb- 
ridges.  Up  to  this  point  the  glacier  ice  has,  perhaps,  been 
restrained  within  valleys,  which  it  has  discovered  and  has 
progressively  widened  and  deepened.  If  the  annual  tem- 
perature continues  to  be  lowered,  there  must  come  a  time 
when  the  ice-feet  from  the  better-nourished  glaciers,  or  from 
those  with  the  shortest  route  to  the  foreland  fronting  the 
range,  will  debouch  upon  the  plain,  spreading  as  they  do  so 
into  fans  or  aprons  (see  plate  10  A).  Later  all  neighboring 
glaciers  may  arrive  at  this  stage,  and  by  spreading  upon  the 
foreland,  coalesce  with  one  another  to  form  a  single  broad 
apron,  such  as  may  be  seen  in  the  Malaspina  glacier  of  Alaska 


38          CHARACTERISTICS  OF  EXISTING  GLACIERS 

(see  plate  10  B).  While  the  glaciers  are  thus  pushing  out 
upon  the  foreland,  they  have  been  deepening  in  their  valleys, 
and  eventually  come  to  overtop  portions  of  the  lateral  comb- 
ridges  of  the  fretted  upland,  thus  moulding  the  sharpened 
needles  into  rounded  shoulders  of  rock.  In  places  the 
glaciers  from  adjacent  valleys  will  flow  together  through  the 
irregular  depressions  separating  peaks,  thus  producing  islands 
or  nunataks. 

But  the  increased  size  of  the  individual  glaciers  of  the 
range  has  corresponded  to  increased  activity  of  cirque  reces- 
sion in  the  high  altitudes,  and  this  has  resulted  in  the  forma- 
tion of  cols  or  passes  through  the  range.  Snow  which  has 
been  divided  at  the  summit,  as  has  water  by  a  divide,  may 
now  be  consolidated  into  glacier  ice  over  the  col  before 
the  separation  is  made.  Thus  it  comes  about  that  without 
a  definite  cirque,  glaciers  will  transect  the  range  flowing  in 
opposite  directions  from  a  central  ice-field.  Such  a  broad 
central  ice-field  is  found  to-day  between  Mount  Newton  of 
the  St.  Elias  group  and  Mount  Logan  to  the  eastward.25 

The  advance  of  the  glacier  ice  up  the  sides  of  the  valleys, 
so  as  partially  to  submerge  the  lateral  comb-ridges,  may 
not  end  until  all  are  thus  covered  and  the  ice  flows  away 
from  the  central  broad  area,  radiating  in  many  directions. 
Here  the  process  of  cirque  recession,  which  has  mainly 
sculptured  the  rock  in  the  higher  altitudes,  comes  to  an  end 
as  we  reach  the  ice-cap  stage  of  glaciation.  Transitions 
toward  such  ice-cap  glaciers  are  to  be  found  to-day  in  the 
Elbruz  and  in  the  Kasbek  region  of  the  Causasus,  where  a 
central  elevated  snow-field  is  the  common  neve  of  several 
glaciers  radiating  in  as  many  directions.26  It  is  of  consider- 
able interest  to  note  that  in  the  Caucasus  district,  at  least, 
there  is  evidence  that  rocky  comb-ridges  are  submerged 
beneath  the  ice  and  make  their  appearance  so  as  to  separate 
the  marginal  ice-tongues.  The  persistence  of  an  ice-cap  over 


HIGH  LEVEL  SCULPTURING  OF  THE  UPLAND        39 

a  mountain  region,  as  is  clear  from  study  of  the  glaciated 
mountains  in  Eastern  Lapland  tends  to  largely  obliterate 
relief  forms  characteristic  of  mountain  glaciers  as  they  are 
replaced  by  the  rounded  shoulders  of  "  rundlings  "  or  the 
smaller  "  roches  moutonnees."  As  soon,  however,  as  nourish- 
ment has  been  so  far  reduced  that  the  higher  points  once 
more  appear  from  beneath  their  snow  cover,  cirque  recession 
will  begin  again,  and,  if  long  continued,  the  evidence  of  the 
ice-cap  will  disappear.  Lack  of  glacial  scratches  or  polish 
in  uplands  sapped  by  this  process  should,  therefore,  not  be 
allowed  to  weigh  too  heavily  in  reconstructing  the  glacial 
history  of  a  district. 

REFERENCES 

1  The  term  "  upland  "  is  here  used  in  a  general  sense  to  designate  any 
relatively  elevated  area  of  the  land. 

2  W.  D.  Johnson,  Jour.  Geol.,  loc.  cit. 

3  A.  C.  Lawson,  "The  Geomorphogeny  of  the  Upper  Kern  Basin,"  Bull. 
Dept.  Geol.  Univ.  Calif.,  vol.  3,  No.  15,  especially  p.  357,  pis.  32,  45. 

4  W.  M.  Davis,  Appalachia,  vol.  10,  1904,  pp.  279-280. 

5  E.g.,  cf.  Scot.  Geogr.  Mag.,  vol.  22,  1906,  pp.  76-89. 

6  "Glacial  Erosion  in  North  Wales,"  Quart.  Jour.  Geol.  Soc.,  vol.  65, 
1909,  pp.  281-350,  pi.   14;  also  "The  Systematic  Description  of  Land 
Forms,"  Geogr.  Jour.,  vol.  34,  1909,  p.  109. 

7  Jour.  Geol.,  loc.  cit. 

8  Ibid.,  loc.  cit. 

9  Wallace  W.  Atwood,  "Glaciation  of   the  Uinta  and  Wasatch  Moun- 
tains," Prof.  Paper,  U.  S.  Geol,  Surv.,  No.  61,  1909,  pp.  1-96,  pis.  1-15. 

10  Other  apt  illustrations  have  been  furnished  by  Lawson  in  a  photo- 
graph taken  in  the  Upper  Kern  region  of  the  California  Sierras  (loc.  cit., 
pi.  32  B),  and  by  Davis  in  a  sketch  made  in  the  Tian  Shan  mountains 
(Appalachia,  vol.  10,  1904,  p.  279). 

11  Loc.  cit.,  pi.  iv. 

12  W.  M.  Davis,  "Glacial  Erosion  in  North  Wales,"  Quart.  Jour.  Geol. 
Soc.,  vol.  66,  1909,  figs.  7,  27,  28. 

13  See  D.  W.  Johnson  and  F.  E.  Matthes,  "The  Relation  of  Geology  to 
Topography."     Reprint  from  Breed  and  Hosmer's  "Principles  and  Prac- 
tice of  Surveying,"  chap,  vii.,  Wiley  &  Co.,  N.Y.,  1908. 

14  Other  quadrangles  of  the  U.  S.  Geological  Survey  which  display  the 
upland  surface  more  or  less  completely  dissected  by  mountain  glaciers  are 
the  following  :  early  stage:  Younts  peak  (Wyoming),  Marsh  peak  (Utah- 
Wyoming),  and  Georgetown  (Colorado);   partial  dissection:   Mount  Lyell 
and  Mount  Whitney  (California),  Grand  Teton  (Wyoming),  Gilbert  peak 


40          CHARACTERISTICS  OF  EXISTING  GLACIERS 

and  Hay  den  peak  (Utah- Wyoming),  and  Silver  ton  and  Anthracite  (Colo- 
rado);    complete  maturity:    Kintla  Lakes  (Montana). 

15  R.  A.  Daly,  "The  Accordance  of  Summit  Levels  among  Alpine  Moun- 
tains," Jour.  GeoL,  vol.  13,  1905,  pp.  117-120. 

16  The  analogy  with  the  forms  produced  by  etching  upon  crystal  faces 
is  so  striking  that  it  may  be  helpful  to  note  it  in  comparison.     The  first 
effect  of  a  reagent  in  its  attack  upon  the  plane  of  a  crystal  face  is  the 
excavation  of  deep  pits  which  have  a  similar  and  wholly   characteristic 
form,   though  the  surface  in  other  places  remains  unchanged.      These 
pittings  later  increase  in  number,  as  they  do  in  size,  and  eventually  they 
mutually  coalesce,  destroying  utterly  the  original  plane  surface,  and  leav- 
ing in  relief  a  series  of  hills  and  ridges  (etch-hills)  projecting  above  a 
somewhat  irregular  floor,  whose  average  level  is  a  measure  of  the  average 
depth  of  the  excavations  made  by  the  process.     The  noteworthy  differ- 
ence between  this  process  and  that  of  cirque  recession  in  glaciated  uplands 
is  that  the  glacial  etch-figures  are  relatively  longer  and  narrower. 

17Penck  und  Bruckner,  "Die  Alpen  im  Eiszeitalter,"  vol.  1,  Leipzig, 
1909,  pp.  284,  et  seq. 

18  Very  likely  originally  from  grate,  fishbone. 

19  The  use  of  combe  in  the  Jura  and  the  Cote  d'Or  for  different  types  of 
valley,  or  of  coombe  in  the  Southern  Uplands  of  Scotland   for  a  glacial 
valley,  being  each  essentially  local  and  having  further  no  relation  to  the 
toothed  article  which  suggests  the  name  comb-ridge,  does  not  constitute 
a  serious  objection  to  this  choice.     Mr.  Matthes  (and  possibly   others) 
have  already  used  the  expression  comb-ridge  in  the  above  described  sense. 
(Appalachia,  vol.  10,  1904,  p.  260). 

20  See  Barker,  "Glaciated  Valley  of  the  Cuchulins,  Skye,"  GeoL  Mag. 
(fig.  4),  vol.  6,  1899,  p.  197  ;  also  "Ice  Erosion  in  the  Cuillin  Hills,  Skye," 
Trans.  Roy.  Soc.  Edinb.,  vol.  40,  1901-1902,  pp.  234-237. 

21  This  characteristic  form  of  cirque,  partly  open  at  the  head,  is  well 
brought  out  in  a  view  published  by  Sir  Andrew  Ramsey  as  early  as  1852, 
Quart.  Jour.  GeoL  Soc.,  vol.  8,  p.  375. 

22  'Argentine-Chilian  Boundary  in  the  Cordillera  de  los  Andes.'  5  vols. 

23  R.  S.  Tarr,  "  Glaciers  and  Glaciation  of  Yakutat  Bay,  Alaska,"  Bull. 
Am.  Geogr.  Soc.,  vol.  38,  1906,  p.  149. 

24  This  term  applied  to  change  of  temperature  of  a  gas,  implies  that  the 
change  is  due  to  change  of  pressure  and  volume  and  not  to  the  communi- 
cation of  heat  from  outside.     The  heating  of  a  bicycle  tire  on  pumping  or 
the  cooling  on  emptying,  may  servo  for  illustration. 

^Filippo  di  Filippi,  "The  Ascent  of  Mount  St.  Elias."    Panorama  at 
end  of  volume  (unnumbered)  from  an  elevation  of  16,500  feet. 

26  H.  Hess,  "Die  Gletscher,"  Braunschweig,  1904,  pp.  65-68. 

27  Penck  und  Bruckner,  "  Die  Alpen  im  Eiszeitalter,"  vol.  1,  Leipzig, 
1909,  pp.  286-287. 


CHAPTER  III 

CLASSIFICATION   OF   GLACIERS    BASED    UPON    COMPARA- 
TIVE ALIMENTATION 

Relation  of  Glacier  to  its  Bed.  —  From  what  has  been  said 
in  the  preceding  section  concerning  the  changes  of  glaciers 
in  correspondence  with  a  progressive  augmentation  of  glacial 
conditions,  it  must  be  evident  that  any  attempt  to  use  each 
circumscribed  body  of  snow  and  ice  as  a  unit  in  name  or  in 
type  will  lead  to  endless  confusion.  Ice  bodies  being  ex- 
tremely sensitive  to  changes  in  annual  temperature,  a  differ- 
ence of  one  degree  may  be  sufficient  to  join  many  ice  bodies 
into  one,  or  to  differentiate  one  body  into  many.  If,  how- 
ever, we  examine  the  distribution  of  snow  and  ice  masses 
within  the  valley  which  they  either  wholly  or  partially 
occupy,  it  will  be  seen  that  there  are  relatively  few  distinct 
glacier  types,  and  that  the  coalescence  of  smaller  ice  masses, 
or  the  breaking  up  of  larger  ones,  does  not  necessarily  alter 
the  type  exemplified. 

The  more  important  types  called  for  by  analysis  on  this 
basis  do  not  differ  greatly  from  those  in  general  use;  but 
the  genetic  relationships  of  these  types  are  here  first  brought 
out,  together  with  distinct  and  intermediate  transitional 
forms.  In  the  following  table,  excepting  the  initial  type  and 
the  glaciers  with  inherited  basins,  the  arrangement  is  in  the 
main  one  of  decreasing  alimentation:  — 

41 


42          CHARACTERISTICS  OF  EXISTING  GLACIERS 

Nivation  type  (Bighorn  glaciers). 
Ice-cap  type  (Jokulls  of  Iceland). 
Piedmont  type  (Malaspina  glacier). 
Transection  type  (Yakutat  glacier). 
Expanded-foot  type  (Davidson  glacier). 
Dendritic  type,  normal  sub-type  (Baltoro  glacier). 

Hanging  glacierets  (Triest  glacier). 

Cliff  glacierets  (Lefroy  cliff  glacieret). 
Dendritic  type,   Tide-water  sub-type    (Harriman-Fjord 

glacier). 
Inherited  basin  type  (Illecillewaet  glacier). 

Reconstructed   type    (Victoria-Lefroy    glacier). 

Volcanic  cone  type  (Nisqually  glacier). 

Cauldron  type  (Caldera  glacier). 
Radiating  (" Alpine")  type  (Nicolaithal  glacier). 
Horseshoe  type  (Mount  Lyell  glacier). 

Nivation  Type.  —  This  type  of  glacier  has  also  been  called 
"  new-born  "  or  "  snowbank  "  glacier,  and  represents  the 
initial  stage  of  glaciation.  Though  small  in  size,  such  glaciers 
differ  markedly  from  those  of  the  same  dimensions  which 
cling  to  the  steep  walls  of  a  large  cirque  (see  horseshoe  glaciers 
below),  which  Tarr  has  referred  to  as  "dying  glaciers."1 
Numerous  examples  of  snowbank  glaciers  are  furnished  by 
the  Bighorn  mountains  of  Wyoming.  Other  known  types 
of  mountain  glaciers  are  all  represented,  and  follow  naturally 
in  sequence  during  a  receding  hemicycle  of  glaciation.  In 
their  discussion  we  shall  conceive  a  mountain  district  to  pass 
by  slow  stages  from  a  culmination  of  glacial  conditions 
toward  a  comparatively  genial  climate. 

Ice-cap  Type.2  —  Though  in  form  and  general  characters 
resembling  so-called  continental  glaciers,  the  ice-caps  by 
reason  of  their  smaller  dimensions  form  a  connecting-link 
with  mountain  glaciers,  and  are  usually  developed  upon 
small  plateaus  or  uplands.  They  correspond  to  conditions 
of  extremely  heavy  snow  precipitation,  and  in  consequence 


CLASSIFICATION   OF  MOUNTAIN  GLACIERS  43 

have  not  been  found  fully  developed  outside  the  polar  or 
sub-polar  regions  (see  inherited  basin  glaciers  below). 

The  normal  type  of  ice-cap  glacier  is  represented  by  the 
mantle  over  Redcliff  peninsula,  north  of  Inglefield  gulf  in 
Greenland.3  It  suffers  no  interruption  from  mountain  peaks, 
but  the  ice  creeps  out  in  all  directions  from  a  central  area, 
and  sends  out  marginal  lobes  and  tongues  which  much  resem- 
ble, save  for  their  whiter  surface,  the  snouts  of  dendritic  and 
radiating  glaciers  (see  below).  The  Jokulls  of  Iceland  are 
very  similar,  and  form  flatly  arched  or  undulatory  domes 
of  ice  having  short  lobes  about  their  margins  (see  plate  11, 1). 
The  largest  of  these,  the  Vatnajokull,  has  an  area  of  8500 
square  kilometres.4  In  Scandinavia  the  smaller  plateau 
glaciers  with  marginal  tongues  of  proportionately  greater 
length,  such  as  the  Jostedalsbiaen,  serve  to  connect  this  type 
with  that  of  the  dendritic  glaciers  (see  plate  11,  2).5  The 
Richtofeneis  on  Kerguelen  island,  recently  described  by  the 
German  South-polar  Expedition,  seems  to  be  very  similar.6 
According  to  Meyer,  the  ice  mass  upon  the  summit  of  Kili- 
mandjaro  in  Africa  is  an  "  ice  carapace,"  having  much  re- 
semblance to  the  ice  plateaus  of  Scandinavia.7 

Piedmont  Type.  —  Piedmont  glaciers,  like  ice-caps,  corre- 
spond to  conditions  of  exceptionally  heavy  precipitation,  and 
are  only  known  from  sub-polar  regions.  In  contrast  to 
small  ice-caps,  the  existing  examples  are  found  in  connection 
with  mountains  of  strong  relief,  so  that  the  snow  and  ice 
which  in  ice-caps  find  their  way  slowly  out  to  the  margin  of  a 
flat  or  gently  sloping  plateau,  are  in  the  piedmont  glacier 
discharged  through  valleys  from  lofty  highlands  to  debouch 
upon  the  foreland  at  the  foot  of  the  range.  The  well-known 
type  is  the  Malaspina  glacier  of  Alaska,  explored  and  de- 
scribed by  Russell  (see  plates  10  B  and  11,  3). 8  Near  it  and 
farther  to  the  west  is  the  Bering  glacier  of  about  the  same 
size.9  To  the  east  of  the  Malaspina  glacier  is  the  Alsek,  a 


44          CHARACTERISTICS  OF  EXISTING  GLACIERS 

much  smaller  piedmont  glacier.10  In  Chili  south  of  42°  S. 
lat.  are  found  other  piedmont  glaciers,  among  them  the  San 
Rafael.11  During  Pleistocene  times  piedmont  glaciers 
existed  in  many  mountain  districts,  notably,  however,  the 
Alps  12  and  the  Rocky  mountains  of  North  America.13  An 
imperfect  transition  from  the  piedmont  type  toward  the 
continental  glacier  is  illustrated  by  the  Friederickshaab 
glacier  in  Greenland,  which  pushes  its  front  out  upon  the 
foreland  as  an  extension  of  the  inland  ice  of  that  continent 
(see  Fig.  94,  p.  171). 

Above  the  ice-apron  and  within  the  range,  the  piedmont 
glacier  bears  a  close  resemblance  to  the  dendritic  type  (see 
below),  though  in  general  it  may  be  said  that  its  valleys 
are  filled  to  a  much  greater  depth.  The  largest  stream 
feeding  the  fan  of  the  Malaspina  glacier  has  been  named 
the  Seward  glacier,  while  other  tributaries  are  known 
as  the  Agassiz  and  the  Tyndall  (see  plates  10  B  and 
11,  3).  It  is  interesting  to  note  that  however  steep  these 
feeders  to  the  ice-apron  may  be,  the  latter  always  shows 
an  exceedingly  flat  slope,  and  is,  moreover,  relatively 
stagnant. 

Transaction  Type.  —  In  a  late  stage  of  augmenting  glacial 
conditions  or  in  an  early  stage  of  the  receding  hemicycle, 
what  is  essentially  one  body  of  ice  may  be  divided  over  a  pass 
and  flow  off  in  opposite  directions  toward  different  margins 
of  the  range.  For  this  type,  exemplified  by  the  Nunatak 
glacier  of  Alaska,  Tarr  has  used  the  term  "  through  glacier," 14 
and  Blackwelder  has  instanced  the  Yakutat  glacier  and 
perhaps  the  Beasley  within  the  same  region.15  Such  glaciers, 
which  may  be  referred  to  as  the  transection  type,  are  often 
the  highways  which  give  readiest  access  to  the  hinterland. 
A  glacier  of  this  type,  which  has  been  carefully  mapped,  is 
the  Sheridan  glacier  near  the  mouth  of  the  Copper  river  in 
Alaska  (see  Fig.  16).16^  An  excellent  panorama  of  one  of  the 


PLATE  10. 


A.    Expanded  fore-foot  of  the  Foster  glacier,  Alaska. 


B.    Type  of  piedmont  glacier. 

(From  a  photograph  of  the  new  model  of  the  Malaspina  glacier  made  under  the 
direction  of  Lawrence  Martin.) 


CLASSIFICATION  OF  MOUNTAIN  GLACIERS 


45 


grandest  transection  glaciers  has  been  furnished  by  Sella.17 
The  glaciation  of  the  Grimsel  pass  in  Switzerland  clearly 
indicates  that  at  one  time  a  glacier  of  this  type  was  parted 
over  the  present  divide,  one  stream  passing  down  the  Rhone 


FIG.  16.  —  Map  of  a  transection  glacier,  the  Sheridan  Glacier  near  the  Copper 
River  in  Alaska  (after  G.  C.  Martin). 

valley,  and  the  other  down  the  Hasli  valley  toward  Meirin- 
gen.  Far  grander  exhibits  of  the  same  sort  are  to  be  found 
in  the  Southern  Andes.18 

Expanded-foot  Type.  —  When  a  piedmont  glacier  draws 
in  its  margin  as  it  shrinks  with  the  coming  of  a  warmer 
climate,  the  several  ice-streams  which  feed  the  apron  of  ice 
upon  the  foreland  end  in  smaller  fans  at  the  mouths  of  the 
individual  valleys.  Perhaps  the  best  known  example  of 
such  an  expanded-foot  glacier  is  the  Davidson,  on  the  Lynn 
canal  in  Alaska,  though  the  Foster  and  Mendenhall  glaciers 
of  the  same  district  are  similar  (see  plate  10  A).  The  Miles 
and  Childs  glaciers,  near  the  Copper  River,  are  also  of  this 
type,  and  have  been  mapped  by  Martin.19  The  transection 
glacier  known  as  the  Sheridan  is  in  the  same  vicinity,  and  has 


46 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


an  expanded  forefoot  —  a  good  illustration  of  the  combina- 
tion of  these  two  types  in  one  (see  Fig.  16).  The  type  par 
excellence  of  the  expanded-foot  glacier  is  the  Baird  glacier 
on  the  Copper  River  (see  Fig.  17). 20  A  larger  but  less 
perfect  example  of  the  expanded  forefoot  than  any  thus  far 
mentioned  is  the  Klutlan,  in  the  Yukon  basin,  whose  foot 
extends  a  number  of  miles  beyond  the  front  of  the  St.  Elias 


FIG.  17.  —  The  Baird  glacier,  a  typical  expanded-foot  glacier  (after  Tarr  and 

Martin). 


21 


range/1  The  Martin  river  glacier  in  the  Copper  river  dis- 
trict affords  another  example,  since  it  expands  for  a  dis- 
tance of  over  20  miles.  It  is,  however,  partially  restrained 
by  a  range  of  hills  rising  on  its  southern  margin,  and  by 
Martin  has  been  considered  intermediate  between  the  pied- 
mont and  valley  types.22 


CLASSIFICATION  OF  MOUNTAIN  GLACIERS 


47 


Dendritic  or  Valley  Type.  —  Retiring  within  the  range  as 
warmer  temperatures  succeed  to  more  rigorous  conditions, 
glaciers  are  of  necessity  restricted  to  individual  valleys  and 
their  tributaries.  They  come  thus  to  have  a  plan  as  truly 
arborescent  as  that  of  water-drainage,  and  they  may  in  this 
stage  be  called  "  dendritic  glaciers."  Unfortunately,  the  term 
"  valley  glaciers,"  in  every  way  appropriate,  has  been  gen- 
erally applied  to  glaciers  which  occupy  valley  heads  only, 
and  hence  the  term  would  have  to  be  redefined  in  its  natural 
rather  than  its  inherited  significance.  This  glacier  type 
geographers  are  most  familiar  with  in  restorations  of  Pleis- 


FIG.  18.  —  Outline  map  of  the  Hispar  glacier,  Karakorum  Himalayas  (after 

Conway) . 

tocene  glaciers,23  but  it  is  none  the  less  a  common  form  to- 
day in  districts  more  distant  from  commercial  centres,  and 
hence  less  easily  accessible  for  study.  From  the  Karakoram 
Himalayas,  the  Baltoro,  Hispar,  and  Biafo  glaciers,  all  of 
this  type,  have  been  described  and  carefully  mapped  by  Sir 
Martin  Conway.24  An  outline  map  of  the  Baltoro  glacier  is 
reproduced  in  plate  11,  4  and  one  of  the  Hispar  glacier  in 
Fig.  18.  Other  valley  glaciers,  generally  less  extensive, 


48 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


have  been  mapped  by  Garwood25  from  the  Kangchenjunga 
Himalayas.  In  the  Central  Tian  Shan  mountains  are  other 
glaciers  of  this  type.26  In  the  New  Zealand  Alps  the  Tasman 
glacier  furnishes  another  example  of  the  same  valley  type 27 
(see  Fig.  19  and  plate  11,  5).  Still  other  examples  have 


FIG.  19.  —  Outline  map  of  the  Tasman  Glacier,  New  Zealand  (after  v.  Lenden- 

feld). 

been  described  from  the   mountains  of  Alaska,  such,  for 
example,  as  the  Kennicott  and  Chistochina  glaciers.28 

Comparison  of  a  number  of  examples  of  valley  glaciers 
may  illustrate  as  many  different  stages  in  the  retreat  of  the 
glacier  from  a  position  in  which  it  occupied  its  entire  valley, 
to  the  retirement  almost  within  the  mother  cirque  at  the 
head.  The  examination  of  the  vacated  valley  has  taught 
us  that  the  tributary  glaciers  erode  their  beds  less  deeply 
than  the  trunk  stream  lying  in  the  main  valley.  It  is  the 
surfaces  of  the  ice-streams  only  that  are  accordant,  and  hence 
a  lack  of  accordance  in  the  bed  levels  has  yielded  the  so-called 
hanging  valleys  with  their  characteristic  ribbon  falls.  No- 
where can  the  hanging  valleys  be  observed  in  greater  perfec- 


PLATE  11. 


XV 


36  Miles 


TYPES   OF   MOUNTAIN   GLACIERS. 

1-2,  ice-cap  types  from  Iceland  and  Norway  respectively  ;  3,  piedmont  type,  Alaska  ; 
4-5,  dendritic  types  from  the  Himalayas  and  New  Zealand  respectively  ;  6,  dendritic 
type  (tidewater  glacier),  Alaska;  7-8,  radiating  types,  Alps  ;  9,  radiating  type,  Hima- 
layas ;  10-12,  horseshoe  types  from  Himalayas,  Selkirks,  and  Canadian  Rockies  re- 
spectively ;  13,  horseshoe  type,  Colorado  ;  14—15,  inherited  basin  types  frcm  Alps  and 
Selkirks  respectively  ;  16,  inherited  basin  type  (reconstructed  glacier),  Canadian  Rockies. 


CLASSIFICATION   OF  MOUNTAIN  GLACIERS 


49 


tion  or  on  a  grander  scale  than  in  the  troughs,  now  largely 
abandoned  of  ice,  which  enter  the  great  fjords  of  the  "inside 
passage  "  to  Alaska  (see  plate  13  A).29 


Mile* 


FIG.  20.  —  Outline  map  of  an  inherited  basin  glacier,  the  Illecillewaet  Glacier  of  the 
Selkirks.     The  dotted  line  is  the  divide  (after  Wheeler). 

As  the  foot  of  the  trunk  glacier  retires  up  its  valley,  the 
lateral  tributaries  which  are  nearest  the  mouth  of  the  valley 


50  CHARACTERISTICS  OF   EXISTING  GLACIERS 

are  at  first  separated  from  it  and  develop  their  own  front 
moraines.  Later  they  are  left  high  above  the  main  stream 
as  a  series  of  "hanging  glacierets"  (see  plate  12).30  The 
series  of  hanging  glacierets,  as  will  be  observed  in  the  maps 
of  the  Baltoro  and  Hispar  glaciers,  often  persist  above  the 
main  valley  well  below  the  foot  of  the  trunk  stream. 

Inherited  Basin  Type.  —  The  dendritic  type  of  glacier 
hardly  appears  in  the  Alps  at  all,  though  the  Great  Aletsch 
glacier  might,  perhaps,  be  regarded  as  a  small  and  imperfect 
example.  The  size  and  characters  of  the  latter  are,  however, 
for  the  district  in  which  it  lies,  abnormal  and  to  be  accounted 
for  by  the  existence  of  a  natural  interior  trough  lying  between 
the  Berner  Oberland  on  the  one  side  and  the  high  range  north 
of  the  Rhone  valley  upon  the  other,  from  which  basin  small 
outlets  only  are  found  through  the  southern  barrier  (plate  11, 
14).  A  better  example,  however,  of  this  special  type  of 
glacier,  in  which  the  inherited  topography  has  exercised  a 
greater  influence  upon  the  glacier  form  than  has  the  auto- 
sculpture,  is  furnished  by  the  Illecillewaet  glacier  of  the 

Selkirks  (see  Fig.  20), 
which,  from  a  roughly 
rectangular  snow-ice  field 
lying  between  parallel 
ridges,  sends  out  short 
tongues  leading  in  differ- 
ent directions.  A  glacier 
of  this  type,  with  a  mod- 
erate increase  only  of 
^ — .'  ;,  -==^Miie9  alimentation,  would  pro- 

FIG.  21.  — Outline  map  of  a  reconstructed      duC6  a  Small  ice-Cap. 

glacier,  the  Victoria  and  Lefroy  glaciers  in  Another   abnormal    f  Orm 

the  Selkirks  (after  Wheeler). 

of  glacier  due  to  the  pe- 
culiarities of  the  basin  which  it  inherited,  is  illustrated  by 
the  Victoria  glacier  in  the  Canadian  Rockies,  a  glacier 


PLATE  12. 


A  hanging  glacieret,  the  Triest  glacier,  above  the  lower  stretch  of  the 
great  Aletsch  Glacier,  Switzerland. 
(After  a  photograph  by  I.  D.  Scott.) 


CLASSIFICATION  OF  MOUNTAIN  GLACIERS  51 

having  no  cirque,  but  only  a  couloir  (the  so-called  "  death- 
trap ")  in  its  stead  (see  Fig.  21).  In  this  case  the  neve 
which  feeds  the  glacier  is  found  high  above  upon  the  cliff  — 
a  true  cliff  glacieret  —  and  this  neve  avalanches  its  com- 
pacted snow  upon  the  surface  of  the  Victoria  glacier,  which 
thus  well  illustrates  the  reconstructed  type.31 

Again,  glaciers  may  develop,  not  upon  a  gently  domed  and 
variously  moulded  pre-glacial  upland  such  as  we  have  thus 
far  had  under  consideration,  but  upon  the  sharply  conical 
volcanic  peaks  which  in  temperate  and  tropical  regions  push 
their  heads  from  the  mountain  upland  at  their  base  far  up 
above  the  snow-line.  In  such  cases,  regular  cirques  cannot 
develop  at  the  heads  of  the  radiating  ice-streams,  but,  on 
the  contrary,  very  irregular  and  mutually  destructive  forms 
will  result  (see  plate  13  B).32  This  is  the  more  true  because 
of  the  loosely  consolidated  tuffs  of  which  such  cones  are 
always  built  up.  If  sufficiently  lofty,  the  result  may  be  a 
small  carapace  or  ice-cap  such  as  is  found  to-day  upon  the 
summit  of  Kilimandjaro  in  Africa.  On  the  other  hand,  a 
partially  ruined  crater  may  furnish  a  natural  basin  or  caul- 
dron for  a  small  glacier  —  cauldron  type.53 

Tide- water  Type.  —  In  high  latitudes  glaciers  sometimes 
descend  to  the  level  of  the  tide-water  in  fjords  which  con- 
tinue their  valleys.  In  such  cases,  the  glacier  front  is 
attacked  mechanically  by  the  waves  and  is  further  melted 
in  the  water.  In  place  of  the  convexly  rounded  nose,  so 
characteristic  of  the  other  types,  there  develops  a  precipitous 
cliff  of  ice  from  which  bergs  are  calved,  and  the  glacier  front 
in  consequence  is  rapidly  retired  (plate  11,  6).  Unhappily, 
the  local  term  "  living  glaciers  "  has  been  applied  to  this 
type  in  Alaska;  "  dead  glaciers,"  in  the  same  usage,  being 
applied  to  glaciers  which  yield  no  icebergs.  The  slopes  of 
the  glacier  surface  and  the  measure  of  projection  of  the  ice 
above  the  water-level  both  render  it  probable  that  in  most 


52          CHARACTERISTICS  OF  EXISTING  GLACIERS 

cases,  at  least,  the  ice-foot  everywhere  rests  on  a  solid  base- 
ment. On  the  other  hand,  the  Turner  glacier,  debouching 
into  Disenchantment  Bay,  Alaska,  shows  a  flat  and  relatively 
low  front  section,  which  is  separated  from  the  remaining  and 
sloping  portion  of  the  glacier  by  a  steep  ice-fall.  This  has 
led  Gilbert  to  think  that  the  lowest  terrace  is  floated  in  the 
water.34 

Radiating  (Alpine)  Type.  —  A  good  deal  of  misunder- 
standing is  current  in  regard  to  alpine  glaciers,  often  unhap- 
pily referred  to  as  valley  glaciers.  Examination  of  any  good 
map  of  Switzerland  suffices  to  show  that  with  the  possible  ex- 
ception of  the  Great  Aletsch,  an  abnormal  type,  Swiss  glaciers 
hardly  extend  into  valleys  at  all.  We  have  too  long  held  the 
alpine  glacier  close  before  the  eye,  and  so  have  much  exag- 
gerated its  importance.  When  Alaskan,  Himalayan,  and 
New  Zealand  glaciers  are  brought  into  consideration,  the 
real  position  of  the  Swiss  type  becomes  apparent.  In  reality 
the  glaciers  of  the  Alps,  far  from  occupying  valleys,  do  not 
even  fill  the  mother  cirques  at  the  valley  heads.  Here  they 
lie,  side  by  side,  joined  to  one  another  like  the  radiating 
sticks  within  a  lady's  fan,  for  which  reason  they  have  some- 
times been  called  Zusammengesetzte  Gletscher  (see  Fig.  22 
and  plate  11,  7).  The  mer  de  glace,  next  to  the  Great  Aletsch 
the  largest  in  Switzerland,  with  its  numerous  tributaries,  it 
is  true,  completely  fills  a  cirque,  but  only  that  of  a  tributary 
valley  (plate  11,  8).35  Alpine  glaciers  are  hence  sheaves  of 
small  glaciers  or  glacierets  which  start  out  from  the  second- 
ary scallops  of  the  mature  cirque.  They  are  wholly  included 
within  the  mother  cirques,  or  fill  and  extend  out  from  the 
secondary  or  tributary  cirques.  In  the  Nicolai  valley  of 
Switzerland,  the  Gorner  glacier  and  its  several  tributaries 
(see  Fig.  22),  with  the  Findelen  and  Langenfluh,  the  Theo- 
dul,  Furgen,  and  Z'Mlitt  glaciers  together,  but  partially  fill 
the  mother  cirque  ofjwhich  Zermatt  is  the  centre.  Lining 


PLATE  13. 


A.    A  hanging  tributary  valley  meeting  a  trunk  glacier  valley  above  the  present 
water-level  on  the  "inside  passage"  to  Alaska. 


B.    Irregularly  bounded  neves  upon  the  volcanic  cone  of  Mt.  Ranier. 


CLASSIFICATION  OF  MOUNTAIN  GLACIERS 


53 


the  valley  below  upon  either  side  are  eighteen  to  twenty 
glacierets,  all  resting  upon  the  albs,  or  high  mountain 
meadows. 

High  up  in  the  Chamonix  valley,  below  the  debouchure  of 
the  mer  de  glace,  similar  glacierets  are  lodged  upon  the  ledge 


i.i.i 


FIG.  22.  —  Outline  map  of  a  radiating  glacier,  in  the  Nicolai  valley,  Switzerland. 

below  the  sharp  needles  of  de  Charmoz,  de  Blatiere,  du  Plan, 
and  du  Midi,  their  frontal  moraines  making  a  continuous 
series  of  scallops  above  the  shoulder  of  the  valley.  Similar 
but  smaller  series  are  shown  in  Fig.  23  and  pi.  14  A. 

Horseshoe  Type.  —  The  final  representative  type  in  our 
series,  unlike  the  alpine  glacier,  is  no  longer  made  up  of  ice- 
streams  joined  together  in  sheaves.  With  further  shrinking 
of  alpine  glaciers  corresponding  to  higher  air  temperatures, 
the  glacier  front  retires  until  it  approaches  the  cirque  wall. 
It  now  takes  on,  either  as  an  individual  or  as  a  collection  of 
small  remnants,  a  broadly  concave  margin,  which  is  in  con- 


54 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


trast  to  the  convex  or  convexly  scalloped  front  character- 
istic of  all  other  glacier  types.  This  type  of  glacieret  has 
been  sometimes  described  under  the  names  "  hanging  "  and 
"  cliff  glaciers." 36  Reasons  have  been  presented  for  restrict- 
ing both  these  terms  to  special  and  different  varieties  of  small 
glaciers  or  glacierets.  It  is  proposed  to  use  here  the  term 
" horseshoe  glacier"  for  these  last  remnants  of  larger  glaciers 


4 


FIG.  23.  —  Outline  map  of  a  horseshoe  glacier,  the  Asulkan  glacier  in  the  Selkirks. 
The  dashed  line  is  the  divide. 

hugging  the  wall  of  the  cirque.  Most  of  the  glaciers  of 
North  America  outside  of  Alaska  belong  in  this  class.  As 
already  implied,  they  are  generally  broader  than  long,  and 
usually  have  concave  frontal  margins.  Excellent  examples 
of  this  type  are  furnished  by  the  Horseshoe  glacier  at 
the  head  of  the  Paradise  valley  in  the  Canadian  Rockies 
and  by  the  Asulkan  glacier  in  the  Selkirks  (see  Fig.  23  and 
plate  14  A).  The  Mount  Lyell  glacier,  long  known  and  cited 


PLATE  14. 


A.   Series  of  hanging  glacierets  which  extend  the  Asulkan  glacier  in  the  Selkirks. 


B. 


View  of  the  Wenkchemna  glacier  at  the  head  of  the  valley  of  the  Ten  Peaks  in 
the  Canadian  Rockies. 


CLASSIFICATION  OF  MOUNTAIN  GLACIERS 


55 


miles 


from  the  High  Sierras  of  California,  is,  however,  an  equally 
good  type.37  For  further  illustration  of  the  type  the  Wenk- 
chemna  glacier  in  the  Canadian  Rockies  has  been  chosen  (see 
Fig.  23,  plates  11,  2  and  14  B).  The  Asulkan  and  Wenk- 
chemna  glaciers 
have  both  been  de- 
scribed by  Scherzer 
as  belonging  to  the 
piedmont  type.  The 
former  hugs  a  cirque 
wall  with  an  in- 
curving frontal  mar- 
gin, and  is  extended 
by  a  series  of  small 
hanging  glacierets 
(see  plate  14  A). 
Unlike  the  piedmont 
glaciers,  it  has  no 
foreland  on  which  to  expand,  but  lies  in  a  cirque  at  the  head 
of  a  typical  U-shaped  valley.  The  Wenkchemna  glacier  oc- 
cupies a  similar  position  in  the  great  cirque  outlined  by  the 
Ten  Peaks  at  the  head  of  a  valley  tributary  to  the  Bow  (see 
Fig.  24)  ,38 

In  plate  11  the  various  types  of  glacier  are  shown  on 
approximately  the  same  scale,  and  from  this  it  will  be  appre- 
ciated that  the  size,  directly  dependent  upon  the  alimenta- 
tion of  the  glacier,  must  be  a  determining  factor  in  classifica- 
tion. The  ice-cap  and  piedmont  glaciers  will  in  this  respect 
overlap,  being  differentiated  by  the  accentuation  of  the  relief 
of  the  land.  For  the  other  types  the  proportion  of  the 
glacier-carved  valley  which  is  still  occupied  by  the  ice  will 
determine  the  form  and  the  more  important  characters  of 
the  existing  glacier.  It  is  important,  therefore,  in  order  to 
determine  the  type  to  which  an  individual  glacier  belongs, 


FIG.  24.  —  Outline  map  of  the  Wenkchemna  glacier 
in  the  Canadian  Rockies.  The  dashed  line  is  the 
divide. 


56  CHARACTERISTICS  OF  EXISTING  GLACIERS 

to  map  the  divide  surrounding  the  valley,  as  well  as  the 
boundaries  of  the  glacier  which  lies  within  it.  It  will  be 
shown  later  that  in  Antarctica,  where  melting  of  snow  or 
ice  occurs  only  under  exceptional  and  local  conditions  some 
additional  glacier  types  are  encountered  (see  chapter  xv). 

REFERENCES 

1  R.  S.  Tarr,  "  Valley  Glaciers  of  the  Upper  Nugsuak  Peninsula,  Green- 
land," Am.  Geol,  vol.  19,  1897,  p.  265  and  fig.  2. 

2  More  fully  described  under  Part  II. 

3T.  C.  Chamberlin,  "Glacial  Studies  in  Greenland,"  IV.,  V.,  Jour. 
Geol.,  vol.  3,  1895,  pp.  199,  470. 

4Th.  Thoroddsen,  "Island,  Grundriss  der  Geographic  und  Geologie, 
V.  Die  Gletscher  Islands,"  Pet.  Mitt.,  Erg.  Bd.  32  (Nos.  152-153),  1906, 
pp.  163-208,  map,  pi.  xii. 

5H.  Hess,  'Die  Gletscher'  (map  3). 

6Emil  Werth,  "Aufbau  und  Gestaltung  von  Kergulen."  Sonderabd. 
aus  Deutsch.  Siidpolar  Expeditionen,  1901-1903,  vol.  2,  pp.  93-183,  pis. 
9-14,  3  maps. 

7  Hans  Meyer,  'Der  Kilimandjaro,  Reisen  und  Studien,'  pp.  436. 
Berlin,  1898  (reviewed  by  Rabot). 

8 1.  C.  Russell,  "An  Expedition  to  Mount  St.  Elias,"  Nat.  Geogr.  Mag., 
vol.  3,  1891,  pp.  52-204,  pis.  2-20.  See  also  Filippi,  loc.  cit. 

9  Roughly  outlined  on  map  of  Alaska  to  accompany  "The  Geography 
and  Geology  of  Alaska,"  by  Brooks  (Prof.  Paper  U.  S.  Geol.  Surv.,  No.  45, 
1906,  plate  in  cover).  For  details  of  marginal  portion  and  description,  see 
G.  C.  Martin,  Bull.  335.  U.  S.  Geol.  Surv.,  1908,  pp.  46-48, and  pis.  1, 2,  and  5. 

10  E.  Blackwelder,  "Glacial  Features  of    the  Alaskan  Coast  between 
Yakutat  Bay  and  the  Alsek  River,"  Jour.  Geol.,  vol.  16,  1907,  pp.  428- 
432,  map. 

11  See  Rabot,  'La  Geographie,'  vol.  3,  1901,  p.  270.     See  also  Hess,  'Die 
Gletscher,'  p.  63. 

12  Penck  u.  Bruckner,  'Die  Alpen  im  Eiszeitalter,'  especially  vol.  2,  1909, 
map  opposite  p.  396. 

13  Fred  H.  H.  Calhoun,  "The  Montana  Lobe  of  the  Keewatin  Ice-sheet," 
Prof.  Paper  No.  50,  U.  S.  Geol.  Surv.,  1906,  pp.  14-21,  map,  pi.  1. 

14  Bull.  Am.  Geogr.  Soc.,  vol.  38,  1906,  p.  149.     See  also  Prof.  Paper  No. 
64,  U.  S.  Geol.  Surv.,  1909,  pp.  35-36,  105,  pis.  vii-viii. 

15  Jour.  Geol,  vol.  16,  1907,  p.  432. 

16  G.  C.  Martin,  Bull.  284,  U.  S.  Geol.  Surv.,  1906,  pi.  12. 

17  Filippi,  loc.  cit. 

18  Argentine-Chilian  boundary,  maps. 

19  G.  C.  Martin,  loc.  cit. 

20  Tarr  and  Martin,  "The  National  Geographic  Society's  Alaskan  Ex- 
pedition of  1909,"  Nat.  Geogr.  Mag.,  vol.  21,  1910,  p.  25. 


CLASSIFICATION  OF  MOUNTAIN  GLACIERS  57 

21  C.  W.  Hayes,  "An  Expedition  through  the  Yukon  District,"  Nat. 
Geogr.  Mag.,  vol.  4,  1892,  pp.  152.     See  also  map  of  Mendenhall  and 
Schrader,  Prof.  Pap.  U.  S.  Geol.  Surv.,  No.  15,  1903,  fig.  4,  p.  41. 

22  G.  C.  Martin,  "Geology  and  Mineral  Resources  of  the  Controller  Bay 
Region,  Alaska,"  Bull.  No.  335,  U.  S.  Geol.  Surv.,  1908,  pp.  48-49,  pi.  i. 
ii.  and  v. 

23  One  of  the  best  maps  of  such  a  restored  valley  glacier  of  Pleistocene 
age  is  that  of  the  Kern  valley  of  California  (see  Lawson,  loc.  cit.,  pi.  xxxi.). 

24  W.  M.  Conway,  **  Climbing  and  Exploration  in  the  Karakoram  Him- 
alayas,"  maps    and  scientific  reports,  1894.     See  also  Fanny  Bullock 
Workman  and  William  Hunter  Workman,  "The  Hispar  Glacier,"  Geogr. 
Jour.,  vol.  35,  1910,  pp.  105-132,  7  pis.  and  map. 

25  E.  J.  Garwood,  "Notes  on  Map  of  the  Glaciers  of  Kangchenjunga, 
with  remarks  on  some  of  the  Physical  Features  of  the  District,"  Geogr. 
Jour.,  vol.  20,  1902,  pp.  13-24,  plate. 

26  Max  Friedrichsen,  "  Die  heutige  Vergletscherung  des  Khan-  Tengri- 
Massives  und  die  Spuren  einer  diluvialen  Eiszeit  in  Tion  Schan,"  Zeitf. 
Gletscherk.,  vol.  2,  1908,  pp.  242-257. 

27  R.  v.  Lendenfeld,  "Der  Tasman  Gletscher  und  seine  Umrandung," 
Pet.  Mitt.,  Erg.  Bd.,  vol.  16,  1884,  pp.  1-80,  map,  pi.  1. 

28  W.  C.  Mendenhall  and  F.  C.  Schrader,  "The  Mineral  Resources  of  the 
Mount  Wrangell  District,  Alaska,"  Prof.  Pap.  U.  S.  Geol.  Surv.,  No.  15. 
1903,  pi.  iv  and  ix.     See  also  Brooks,  Prof.  Pap.  U.  S.  Geol.  Surv.,  No.  45, 
map,  pi.  xxxiv. 

29  R.  S.  Tarr,  "Glacier  Erosion  in  the  Scottish  Highlands,"  Scot.  Geogr. 
Mag.,  vol.  24,  1908,  pp.  575-587. 

30  The  term  "hanging  glacier,"  now  used  in  a  variety  of  senses,  is,  it  is 
believed,  best  retained  with  the  restricted  meaning.     The  term  "cliff 
glacier,"  generally  considered  synonymous,  may  be  restricted  to  the  long 
strips  of  incipient  glacier  ice  which  sometimes  parallel  the  main  valleys  on 
narrow  terraces  above  precipitous  cliffs  which  are  primarily  determined 
by  the  rock  structure  (see  ante,  p.  54;   and  also  Matthes,  Appalachia, 
vol.  10,  1904,  p.  262).     In  the  sense  here  employed,  a  hanging  glacier  is 
generally  the  equivalent  of  the  Kahrgletscher,  a  term  quite  generally  em- 
ployed in  Germany.     The  term  "horseshoe  glacier"  we  have  here  sug- 
gested for  an  essentially  different  type  of  glacieret  (see  p.  53). 

31  See  map  and  description  of  this  glacier  by  Scherzer,  "Glaciers  of  the 
Canadian  Rockies  and  Selkirks,"  Smith.  Contrib.,  No.  1692,  1907,  chaps. 
2-3. 

32  Cf.  I.  C.  Russell,  "Glaciers  of  Mount  Ranier,"  18th  Ann.  Rept.  U.  S. 
Geol.  Surv.,  1898,  pp.  329-423. 

33  Hans  Meyer,  "Der  Calderagletscher  des  Cerro  Altar  in  Equador," 
Zeitsch.  f.  Gletscherk.,  vol.  1,  1906-1907,  pp.  139-148. 

34  G.  K.  Gilbert,  *  Harriman  Alaska  Expedition,'  vol.  3,  "  Glaciers,"  1904, 
pp.  67-68.    See  also  Tarr  and  Butler,  "  The  Yakatat  Bay  Region,  Alaska, 
Physiography  and  Glacial  Geology."    Prof.  Paper  No.  64,  U.  S.  Geol.  Surv., 
1909,  pp.  39,  40,  pi.  xa. 


58          CHARACTERISTICS  OF  EXISTING  GLACIERS 

35  This  valley  is  a  large  hanging  valley  tributary  to  the  Chamonix  val- 
ley, which  latter  alone  is  comparable  in  size  to  those  that  form  the  beds 
of  the  Baltoro,  Hispar,  and  Tasman  glaciers.    If  at  first  it  seems  that  con- 
fusion may  result  from  the  introduction  of  valleys  of  different  orders  of 
magnitude,  a  second   thought  suffices  to  show  that  the  difficulty  is  of 
theoretical  rather  than  of  practical  importance,  at  least  so  far  as  existing 
examples  of  glaciers  are  concerned. 

36  See  footnote  on  p.  57. 

37 1.  C.  Russell,  "Existing  Glaciers  of  the  United  States,"  5th  Ann. 
Kept.  U.  S.  Geol.  Surv.,  1885,  pp.  314-328,  pi.  40. 

38  Sherzer,  Smith.  Contrib.,  No.  1693,  1907,  chaps,  iv.  and  vii.  The  only 
resemblance  to  the  piedmont  glacier  is  in  the  shape.  Neither  glacier  ex- 
pands upon  a  foreland,  but  both  lie  in  cirques  at  the  heads  of  U-shaped 
valleys.  They  have  no  appreciable  tributaries,  and,  as  already  pointed 
out,  piedmont  glaciers  are  necessarily  of  large  size,  corresponding  to  ex- 
cessive precipitation. 


CHAPTER  IV 

LOW  LEVEL   GLACIAL   SCULPTURE   IN   MODERATE 
LATITUDES 

The  Cascade  Stairway.  —  No  one  who  has  climbed  a  moun- 
tain glacier  to  its  neve  has  failed  to  be  struck  by  the  alter- 
nation of  plateau  and  precipitous  slope,  for  the  surfaces  of 
mountain  glaciers  are,  with  few  exceptions,  broken  into 
broad  terraces.  Each  steep  descent  is  well  understood  to 
overlie  a  corresponding  fall  in  the  glacier-bed.  Perched  upon 
the  high  cliffs  which  overlook  the  Pinnacle  pass  during  his 
first  attack  upon  Mount  St.  Elias,  the  late  Professor  Russell 
wrote  of  these  terraces : 1  - 

Were  the  snow  removed  and  the  rock  beneath  exposed,  we 
should  find  terraces  separated  by  scarps  sweeping  across  the  bed 
of  the  glacier  from  side  to  side.  Similar  terraces  occur  in  glaciated 
canyons  in  the  Rocky  Mountains  and  the  Sierra  Nevadas,  but  their 
origin  has  never  been  explained.  The  glacier  is  here  at  work 
sculpturing  similar  forms,  but  still  it  is  impossible  to  understand 
how  the  process  is  initiated. 

The  generalized  description  of  uncovered  glacier-beds 
within  the  High  Sierras  of  California  —  perhaps  as  well  as 
any  that  has  been  penned  —  lays  the  emphasis  upon  the 
more  essential  and  impressive  characters : 2  - 

"  The  amphitheatre  bottom  terminated  forward  in  either  a  cross 
cliff  or  a  cascade  stairway,  descending,  between  high  walls,  to  yet 
another  flat.  In  this  manner,  in  steps  from  flat  to  flat,  common 

59 


60          CHARACTERISTICS  OF  EXISTING  GLACIERS 

enough  to  be  characteristic,  the  canyon  made  descent  (see  Fig. 
25  and  plate  15).  In  height,  however,  the  initial  cross  cliff  at  the 
head  dominated  all.  The  tread  of  the  steps  in  the  long  stairway, 
as  far  as  the  eye  could  follow,  greatly  lengthened  in  down-canyon 
order. 


\\zoo- 

IOZOO'- 


9SOO'- 


FIG.  25.  —  Longitudinal  section  along  a  glaciated  mountain  valley,  showing  re- 
versed grades  and  rock  basin  lakes  in  series.  Vertical  scale  about  two  and  one 
half  times  the  horizontal  (after  Salisbury  and  Atwood3). 

The  grade  on  the  treads  is  often  reversed,  so  that  rock 
ridges  separate  basins  or  colks,  and  these  latter  come  to  be 
occupied  by  the  characteristic  glacial  lakes.  High  up  in  the 
valley,  where  the  treads  are  relatively  short,  these  lakes  are 
more  ar  less  kettle-shaped,  though  relatively  shallow,  and 
they  usually  rest  directly  upon  the  rock.  They  are,  there- 
fore, often  referred  to  as  rock  frasw  lakes,  though  a  morainal 
dam  sometimes  plays  a  part  in  impounding  the  water 
(Fig.  44,  p.  82).  Often  connected  together  like  pearls  upon  a 
thread,  or,  better  still,  like  the  larger  beads  in  a  rosary,  they  are 
sometimes  referred  to  as  pater  noster  lakes 4  (see  Fig.  12,  p.  28). 
Lower  down  in  the  valley  and  upon  the  longer  treads,  lakes 
are  more  apt  to  be  long  and  ribbonlike  in  form  (see  plate  15). 

Mechanics  of  the  Process  which  produces  the  Cascade 
Stairway.  —  Since  Russell's  meditation  above  the  Pinnacle 
pass,  nearly  a  score  of  years  ago,  considerable  study  has  been 
given  to  the  subject  of  erosion  upon  the  glacier-bed.  In 
the  Alps,  Penck  and  Bruckner  have  enunciated  their  "  law 
of  adjusted  cross-sections."  The  glacier,  on  invading  the 
mature  river-valley,  characterized  by  uniformly  forward 
grades  and  by  accordance  of  trunk  with  side  valleys,  will, 
in  general,  be  so  modified  that  a  small  cross-section  corre- 
sponds to  a  deepening  of  the  valley.5  Thus  may  be  brought 


PLATE  15. 


Land  surface  moulded  by  mountain  glaciers  near  the  ancient  Lake  Mono,  east 
of  the  Sierra  Nevadas  in  California  (after  Russell). 


GLACIAL  SCULPTURE  IN  MODERATE  LATITUDES         61 

about  the  hanging  side  valley,  and  a  local  modification  of, 
and  perhaps  even  a  reversal  of,  direction  in  the  grade  of  the 
main  valley. 

If  the  rock  be  not  homogeneous  throughout,  or  if  it  be 
unequally  intersected  by  joint  planes,  further  abrupt  changes 
in  grade  will  result.  The  two  processes  which  are  effective 
in  deepening  the  bed  of  the  valley  are  well  recognized  to 
be  abrasion  and  plucking.  Greater  softness  in  the  rock 
will  correspond  to  greater  depth  of  abrasion,  while  the 
perfection  of  the  parting  planes  will  directly  determine 
the  amount  of  quarrying  in  the  rock  by  plucking.  Abra- 
sion being  greatest  on  the  upstream  side  of  any  irreg- 
ularity in  the  bed,  and  plucking  being  largely  restricted  to 
the  downstream  side,  the  tendency  of  these  processes  work- 
ing together  will  be  to  produce  steps  of  flat  tread  but  steep 
riser,  the  latter  coinciding  with  the  nearly  perpendicular 
planes  of  jointing.  To  quote  de  Martonne,6  "  the  mass  of  the 
ice  does  not  rest  everywhere  upon  its  bed,  and  in  particular 
upon  the  risers  of  steps  (Mer  de  Glace,  Fiesch,  Rhone  glacier). 
Speaking  generally,  the  contact  becomes  closer  with  each 
diminution  of  the  down  slope;  it  tends  to  be  relaxed  with 
each  increase  of  the  slope." 

It  is  further  probable  that  the  cliffs  at  the  lower  margins 
of  the  terraces  are  in  many  cases,  at  least,  considerably  re- 
cessed through  the  operation  of  a  sapping  process  in  every 
way  analogous  to  that  which  obtains  at  the  base  of  the 
Bergschrund,  or  Randspalte.  So  soon  as  the  rock  cliff  has 
been  formed,  either  below  a  narrowing  of  the  valley  or 
where  a  hard  layer  of  rock  transects  it,  the  glacier  will  de- 
scend over  it  in  an  ice-fall,  showing  gaping  transverse  cre- 
vasses. These  fissures  in  the  ice  may  be  sufficiently  profound 
to  admit  the  warm  air  at  midday  to  the  rock  joints,  and  so 
bring  about  with  the  nightly  fall  of  temperature  a  me- 
chanical rendering  of  the  rock. 


62 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


Basal  cliff  sapping  being  downward  as  well  as  backward, 
the  reversed  grades  of  the  treads  in  the  staircase  could  be 
thus  explained.  In  the  Alps,  Penck  distinguishes  especially 
one  larger  cliff  in  the  staircase  which  separates  the  head 
cirque  from  the  trough  valley  (Trogthal).7 

The  extended  studies  of  Penck  and  Bruckner  upon  the 
Alps  have  shown  that  as  a  general  rule  the  risers  of  the  steps 
are  found  just  above  the  junction  of  the  main  valley  with 


FIG.  26.  —  Rock  bar  with  basin  showing  above,  from  the  Upper  Stubaithal  near 
the  Dresdner  Hiitte  (after  Bruckner). 

its  tributaries.8  Thus  the  main  glacier  stream  is  here  re- 
inforced by  large  contributions  of  ice  and  accomplishes  a 
larger  amount  of  excavating  upon  its  bed.  Sausage-like 
the  valleys  widen  below  the  steps  so  that  deeper  basins 


GLACIAL  SCULPTURE   IN  MODERATE  LATITUDES         63 

alternate  with  higher  narrows  and  afford  a  certain  corre- 
spondence between  the  plan  and  the  profile  of  the  valley. 

Owing  to  the  backward  tilt  of  the  treads  within  this  cascade 
stairway,  their  outer  edges  rise  from  the  sanded  and  in  part 
flooded  floor  in  the  form  of  a  rocky  bar  which  crosses  the 
valley  from  side  to  side.  These  bars  are  the  well-known 
Riegel 9  or  verrous 10  of  the  Swiss  Alps,  which  for  want  of  a 
better  English  designation  we  may  term  "rock  bars."  The 
topographic  form  of  such  bars  is  well  brought  out  in  Fig. 
26.  In  many  Alpine  valleys  such  bars  are  quite  numerous, 
no  less  than  eight  being  encountered  in  a  walk  down  the 
Haslithal  from  the  Grimsel  to  Meiringen.  The  largest  and 
best  known  of  these  is  the  famous  Aarschlucht  near  Meirin- 
gen. Many  of  the  larger  Riegel  are  found  to  correspond  in 
position  to  the  outcropping  of  a  zone  of  limestone,  which, 
being  less  easily  eroded  by  the  glaciers  than  is  the  sur- 
rounding gneiss  rock,  has  in  consequence  been  left  in  relief.11 

The  U -Shaped  Glacier  Valley.  --To-day  it  is  everywhere 
recognized  that  one  effect  of  the  occupation  of  valleys  by 
mountain  glaciers  is  to  so  transform  them  that  the  cross- 
section  has  the  form  of  a  letter  U.  The  steepness  and  the 
height  of  the  side  walls  will,  in  hard  rocks  at  least,  be  to 
some  extent  a  function  of  the  depth  to  which  the  valleys 
have  been  filled  by  the  glaciers.  Thus  the  Little  Cotton- 
wood  canyon  on  the  western  front  of  the  Wasatch  range,  so 
often  cited  and  figured  as  a  typical  U-valley  (see  plate  16  A), 
is  one  in  which  the  ice-foot  pushed  out  but  a  short  distance 
beyond  the  portal  of  the  valley.  At  this  point,  therefore, 
the  valley  was  occupied  by  ice  to  a  very  moderate  depth, 
and  it  is  the  bottom  portion  only  which  betrays  the  curve 
of  the  U-section.  In  the  higher  Alpine  valleys,  on  the 
other  hand, — which  were  once  filled  to  a  much  greater  depth, 
— the  steep  undercut  side  walls  often  complete  the  form  of  the 
letter  U.  Their  intersection  with  an  earlier  valley  located 


64          CHARACTERISTICS  OF  EXISTING  GLACIERS 

on  the  same  general  line,  but  at  a  higher  level,  has  developed 
rather  sharp  shoulders.  These  remnants  of  the  earlier 
valley  are  the  albs,  or  high  mountain  meadows,  so  common 
along  the  Swiss  valleys  (see  Fig.  27). 

The  form  of  these  remnants  of  older  and  now  higher 
valley  floors,  is  not  that  of  a  water-worn  valley,  but  gener- 
ally is  a  relatively  shallow 
glacier-carved  trough.  They, 
therefore,  indicate  that  since 
sluggish  glaciers  carved  the 
earlier  valley,  a  new  uplift 
of  the  range  has  taken  place.12 

FIG.  27.  -Ideal  cross-action  of  a  U-shaped  Subsequent      to      the     Uplift, 

valley  once  occupied  by  a  mountain  the  glacier  acquired  a  steeper 

gradient  and  carved  its  bed 

below  the  middle  of  the  older  U -valley,  as  are  the  Norwe- 
gian valleys  likewise  to  be  explained  through  an  uplift  of 
the  land. 

It  is  clear  that  the  widening  of  the  valley  bottom  is  accom- 
plished by  the  ice  through  the  combined  abrading  and  pluck- 
ing processes.  As  is  true  of  so  many  geological  processes, 
the  direct  attack  is  here  through  a  limited  range  only,  but 
is  extended  upward  and  made  more  effective  through  under- 
mining or  sapping.  The  dividing  line  between  the  vertical 
zones  of  direct  and  indirect  action  —  of  ice  erosion  and  of 
undermining  —  is  often  a  sharp  line.  The  upper  zone 
quarried  by  the  undermining  process,  here  always  greatly 
facilitated  by  frost  rending,  develops  irregular  but  nearly 
vertical  (joint)  surfaces.  The  lower  eroded  surface,  on  the 
other  hand,  is  rounded  into  shoulders  (roches  moutonnees), 
and  is  further  smoothed  and  scratched  (see  Fig.  28  arid 
plate  16  B).  This  line  of  sharp  separation  may  be  con- 
tinued up  the  valley  and  there  be  joined  to  the  schrund  line 
of  the  cirque  (see  Fig.  6,  p.  18). 


PLATE  16. 


A.    The  Little  Cottonwood  Canyon  in  the  Wasatch  Range  transformed  at  the 
bottom  into  the  characteristic   U  section. 

(After  a  photograph  by  Church.) 


B.    Striated  surface  of  glaciated  valley  floor  near  Loch  Coriusk,  Skye. 
(.From  a  photograph  by  B.  Hobson.) 


GLACIAL  SCULPTURE  IN  MODERATE  LATITUDES     65 

The  areas  of  the  valley  section  taken  at  different  levels 
obviously  stand  in  direct  relation  to  the  size  of  the  glacier 
at  those  levels.  When  the  glacier  ended  within  the  valley 
(dendritic  glacier),  ablation  in  the  lower  levels  diminished 


FIG.  28.  —  View  in  the  glaciated  Sierra  Nevadas  of  California,  showing  the  sharp 
line  which  sometimes  separates  the  zone  of  abrasion  from  that  of  sapping  (after 
a  photograph  by  Fairbanks.) 

the  width  of  the  ice-stream  as  its  foot  was  approached.  In 
some  cases,  the  glacier  never  reached  the  margin  of  the  up- 
land, in  which  event  the  lower  portion  of  the  valley  is 
relatively  narrow  and  reveals  the  characteristic  section  of 
a  river-carved  valley.  Even  when  widened  by  glaciation, 
the  widest  section  may  be  found  considerably  above  the 
lowest  limits  of  the  ice  advance.  This  is  illustrated  by 
Big  Cottonwood  canyon  in  the  Wasatch  range,  which  at  its 
portal  is  a  narrow  V-shaped  valley,  but  which  above  has 
been  widened  by  glaciation.13 

Wherever,  on  the  other  hand,  mountain  glaciers  have  been 


66 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


so  amply  nourished  as  to  expand  beyond  the  margin  of  the 
upland,  the  valley  is  found  to  widen  rapidly  towards  its 
mouth  and  expands  to  the  foreland  in  trumpet  form.  This 
is  well  illustrated  by  the  portals  of  the  larger  Alpine  valleys, 
which  once  supported  piedmont  glaciers  (see  Fig.  47,  p.  85). 
It  has  been  urged,  by  those  who  regard  the  glacier  influ- 
ence as  always  protective  to  its  bed,  that  the  deep  U -valleys 
have  in  pre-glacial  or  in  inter-glacial  times,  been  cut  down  by 
rivers,  and  that  these  narrow  valleys  the  glaciers  have  sub- 
sequently widened.  Some  part  the  gorges  of  mountain 
streams  must  have  played,  particularly  in  inter-glacial 
times  when  the  glacier-formed  rock  bars  had  been  sawed 
through  by  the  torrents  which  followed  the  retreat  of  the 
glacier  from  portions  of  its  valley. 

While  nearly  all  glacialists  seem  to  be  agreed  that  a  widen- 
ing of  valley  bottoms  results  from  the  occupation  by  moun- 
tain glaciers,  many  are  unwilling  to  admit  that  there  is  in 
addition,  a  deepening  of  the  valley  through  the  action  of  the 
same  processes.  To  the  present  writer  the  evidence  for  the 

overdeepening  in- 
herent in  the  cross 
profiles  of  valleys 
is  convincing. 

The  Hanging  Side 
Valley.  -  -  Whereas 
under  normal  con- 
ditions of  sub-aerial 
erosion,  the  indi- 
vidual tributary 
valleys  meet  the 
main  valley  at  a 
common  level,  or 
accordantly  (see  Fig.  29),  this  is  not  true  of  glaciated 
valleys.  Since  the  smaller  tributary  glaciers  are  unable  to 


FIG.  29.  —  Normal  valleys  from  sub-aerial  erosion  — 
accordant  drainage  (after  Davis). 


GLACIAL  SCULPTURE  IN   MODERATE  LATITUDES      67 


erode  their  beds  as  effectively  as  the  larger  trunk  streams, 
when  both  have  been  vacated  by  the  ice,  side  valleys  are 
found  to  have  their  beds  standing  above  the  general  level 
of  the  main  valley  —  they  are  not  accordant  as  are  the  trib- 
utary valleys  of 

Wt;^ 

^M//w 


rivers  —  and  they 
are  in  consequence 
spoken  of  as  "hang- 
ing valleys "  (see 
Fig.  30).  Unlike 
those  tributaries 
which  have  never 

been      OCCUpied     by     FIG.  30.  —  Glaciated  and  non-glaciated  valleys  tribu- 


tary to  a  glaciated    main  valley.     Both  types    of 
side  valley  are  hanging  (after  Davis). 


glaciers,  they  are 
found  to  be  too 
large  for  the  streams  which  now  flow  in  them.  This  stream 
drops  over  the  steep  U-wall  into  the  main  valley  in  the 
characteristic  ribbon  type  of  waterfall  found  in  such  num- 
bers in  every  glaciated  mountain  district. 

As  pointed  out  by  Penck,  it  is  the  surfaces  only  of  main  and 
tributary  glaciers  that  are  accordant,  or  at  common  level. 
It  is,  perhaps,  profitable  to  consider  for  a  moment  why  it  13 
that  the  tributaries  of  water-streams  should,  under  normal 
conditions,  be  accordant,  as  was  long  ago  pointed  out  to  be 
the  rule  by  Play  fair;  whereas  the  beds  of  tributary  glacier 
streams  enter  the  main  valley  above  the  level  of  its  floor. 
In  both  cases  the  tributaries  are  notably  smaller  than  the 
main  stream.  The  abrading  process  by  which  the  water- 
stream  lowers  its  bed  is  in  no  wise  dependent  upon  the  depth 
or  volume  of  water,  for  water-streams  have  a  cutting  power 
directly  determined  by  the  gradient  of  their  bed  and  increas- 
ing at  a  marvellous  rate  with  increase  of  slope.  Now  trib- 
utary valleys  in  mountain  districts  have  gradients  which 
are  much  steeper  than  that  of  the  main  valley  near  the  point 
of  their  junction  (see  Fig.  31). 


68 


CHARACTERISTICS   OF  EXISTING  GLACIERS 


In  the  glacier  stream  floor,  gradient  evidently  plays  a 
much  less  important  role  in  the  abrasion  of  the  bed,  while 
depth  of  ice  would  appear  to  be  a  determining  factor,  the 


FIG.  31.  —  Comparison  of  the  longitudinal  profiles  of  a  mature  stream-cut  valley 
and  its  tributaries  with  a  glacier-carved  Alpine  valley  and  its  tributaries.  Note 
how  in  both  instances  the  average  gradient  of  the  tributaries  is  always  in  excess 
of  that  of  the  main  valley,  near  the  junction  (after  scaled  profiles  prepared  by 
Nussbaum14). 

friction  between  the  stones  by  which  the  glacier  is  shod  and 
the  rock  floor  causing  a  correspondingly  greater  wear.  The 
hollowing  of  flagstones  is  proportional,  not  only  to  the  num- 
ber of  footsteps  which  have  come  in  contact  with  the  stones, 
but  also  upon  the  weight  of  the  individuals  and  the  number 
of  projecting  nails  upon  their  boot  heels. 

REFERENCES 

1 1.  C.  Russell,  "Expedition  to  Mount  St.  Elias,"  Nat.  Geogr.  Mag., 
vol.  3,  1891,  pp.  132-133. 

2  Johnson,  Jour.  GeoL,  vol.  12,  1904,  pp.  570-571. 

3  The  interpretation  of  topographic  maps,  Prof.  Pap.  No.  60,  U.  S. 
GeoL  Surv.,  1908,  p.  66. 

4  Nussbaum,  "  Die  Taler  der  Schweizeralpen,"  Bern,  1910,  p.  28. 


GLACIAL  SCULPTURE   IN  MODERATE  LATITUDES     69 

6  A.  Penck,  Jour.  GeoL,  vol.  13,  1905,  pp.  1-19. 

6  Em.  de  Margerie,  "Sur  I'inegale  repartition  de  1'erosion  glaciare  dans 
le  lit  des  glaciers  alpins,"  C.  R.  Acad.  Science,  Paris,  December  27,  1909, 
pp.  1-3  (reprint). 

7  See  also  Nussbaum,    "Die  Taler  der  Schweizeralpen,"  Bern,  1910, 
pi.  2,  figs.  2-4. 

8  Ed.  Bruckner,  "Die  glazialen  Ziige  im  Antlitz  der  Alpen,"  I.e.,  1910, 
p.   787 ;  also  Fritz    Nussbaum,   "  Die  Taler  der   Schweizeralpen,   Eine 
geographishe  Studie,"  Bern,  1910,  3  pis.  and  12  figs. 

9  Bruckner,  I.e.,  p.  787. 

10  De  Martonne,  "Sur  la  genese  des  formes  glaciares  Alpines,"  C.  R. 
Acad.  Sci.,  Paris,  January  24,  1910,  p.  1  (reprint). 

11  Bruckner,  I.e.,  p.  790. 

12  Albrecht  Penck,  "The  Origin  of  the  Alps,"  Bull.  Am.  Geogr.  Soc.,  vol. 
41,  1909,  p.  68. 

13  w  w.  Atwood,  "Glaciation  of  the  Uinta  and  Wasatch  Mountains," 
Prof.  Pap.  U.  S.  Geol.  Survey,  No.  61,  1909,  pp.  85-88,  pi.  x. 

"Nussbaum,  I.e.,  1910,  final  plate. 


CHAPTER  V 

HIGH  LATITUDE  GLACIAL  SCULPTURE 

Variations  in  Glacial  Sculpture  Dependent  upon  Lati- 
tude. —  Thus  far  we  have  considered  mountain  glaciers  in 
those  districts  which  are  most  accessible  for  study,  and  hence 
are  better  known  —  mountain  districts  within  moderate 
latitudes,  in  which  the  snow-line  is  from  7000  to  12,000  feet 
above  sea,  and  where,  in  consequence,  there  is  high  relief 
and  correspondingly  steep  gradients.  Moreover,  in  most 
of  these  districts  the  surface  upon  which  the  mountain 
glaciers  whose  handiwork  we  may  study,  began  their  carv- 
ing process  was  a  surface  moulded  by  the  water-streams  of  a 
humid  region  —  the  initial  surface  in  the  glacial  cycle  was 
a  product  of  sub-aerial  erosion.  The  results  are  not  in  all 
respects  the  same  in  those  higher  latitudes  where  the  snow- 
line  descends  to  near  the  sea-level,  and  where  in  Pleistocene 
times,  a  continental  glacier  largely  planed  away  the  irregu- 
larities of  earlier  erosion  periods,  leaving  a  hard  rock  sur- 
face, but  slowly  acted  upon  by  the  well-known  weathering 
processes. 

The  low  level  of  the  snow-line  is  here  further  responsible 
for  the  development  of  the  subsequent  mountain  glaciers 
where  there  is  only  moderate  relief,  so  that  glacier  streams 
developed  on  low  gradients  were  notably  sluggish  in  their 
movements.  Inasmuch  as  the  sub-polar  regions  particularly 

70 


HIGH  LATITUDE  GLACIAL  SCULPTURE 


71 


have  been  characterized  within  the  recent  geological  period 
by  rather  remarkable  uplifts  of  the  land,  this  elevation  has 
had  an  important  bearing  on  the  origin  of  the  surface  fea- 
tures there  developed. 

Surface  Features  of  Northern  Lapland.  —  A  visit  to 
Northern  Lapland  is  in  this  regard  most  enlightening  to  one 
who  has  observed  glacial  carving  in  lower  latitudes  only. 
In  the  lower  levels  of  these  Northern  regions,  which  lie  to  the 
eastward,  where  the  land  was  relatively  low,  and  where  the 
prevailing  winds  had  already  given  up  much  of  their  mois- 
ture, mountain  glaciers  have,  in  consequence,  found  little 
to  nourish  them.  Here  is  found  to-day  a  surface  of  low, 
bare  hills,  rounded  and  smoothed  and  betraying  the 
sculpture  of  continental  ice  masses  alone  (see  Fig.  35  a). 


TIG.  32.  —  Characteristic  surface  in  Swedish  Lapland  which  has  been  moulded 
mainly  by  the  continental  glaciers  of  Pleistocene  times.  The  low  central  trough 
is,  however,  the  work  of  a  subsequent  mountain  glacier  on  a  low  gradient  — 
the  Karso  trough  valley  (after  O.  Sjogren). 

The  surface  which  still  shows  the  features  moulded  by 
erosion  beneath  the  continental  glacier,  would  appear  to 
extend  far  to  the  northeastward.  To  quote  Feilden *  on  the 
Kola  Peninsula :  "  As  we  sail  eastward  along  the  Murrnan 


72 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


coast  of  Russian  Lapland,  we  see  on  our  right  hand  a  bold 
and  precipitous  country.  Its  highest  summits  appear  to  rise 
to  500  or  600  feet.  The  hills  are  planed  down  to  a  general 
level,  and  no  peaked  mountain  breaks  the  monotony  of  the 
scene." 2 

The  Flatly  Grooved  Glacier  Valleys  and  the  Scattered 
Knobs.  —  In  the  somewhat  higher  levels  farther  to  the  west- 
ward, but  before  the  high  Norwegian  plateau  is  reached,  the 
handiwork  of  mountain  glaciers  is  recognized,  though  no  ice 
masses  are  here  in  evidence  to-day.  Locally,  where  were 
centres  of  dispersion,  the  characteristic  "  arm-chair  "  form 
of  the  glacial  cirque  is  to  be  seen,  and  well  developed  karlings 
are  made  out,  though  here  the  jagged  pinnacles  so  common 
in  lower  latitudes,  are  seldom  seen  (see  Fig.  33).  Out  from 


FIG.  33.  —  Map  of  a  portion  of  the  area  south  of  Tornetrask  in  Swedish  Lapland 
showing  the  cirques  and  karlings  developed  by  mountain  glaciers  subsequent  to 
the  continental  glaciation. 

these  centres  of  late  mountain  glaciation,  the  sluggish  glacier 
streams  have  channelled  broad  and  gently  hollowed  grooves 
within  the  former  undulating  surface.  These  shallow  val- 
leys have  but  little  in  common  with  the  deep  U -channels 


HIGH  LATITUDE  GLACIAL  SCULPTURE 


73 


of  the  Alpine  highland.  Where  these  streams  have  been 
numerous  and  of  nearly  equal  size,  they  have  coalesced  and 
so,  to  a  large  extent,  have  occupied  the  country,  leaving  a 
smoothed  floor  out  of  which  more  or  less  elongated  knobs 
of  rock  rise  on  abrupt  or  even  precipitous  slopes  (see  Figs. 
33  and  34).  Where  relatively  large  streams  have  channelled 


FIG.  34.  —  Glacial  surface  crossed  by  shallow  channels  carved  by  sluggish  mountain 
glaciers  on  a  surface  of  slight  relief.  The  area  is  south  of  Tornetrask  in  Swedish 
Lapland  (after  O.  Sjogren). 

the  surface  guided  by  pre-existing  valleys,  the  horizon  lines 
now  show  broad  depressions  resembling  the  bite  of  some 
gigantic  monster.  The  Lapporten,  or  Lapp's  Gate,  which  is 
seen  in  so  many  views  about  Tornetrask,  furnishes  a  strik- 
ing illustration  (see  Fig.  35  b). 

The  Fjords  of  Western  Norway.  —  In  the  plateau  region  of 
Norway  still  further  to  the  westward,  where  the  heavier 
precipitation  and  the  much  higher  elevations  have  made  it 
possible  for  glaciers  to  persist  to  the  present  day,  such  flat 
U -channels  may  now  be  seen  high  up  upon  the  level  of  the 
plateau  (see  Fig.  35  c).  Similarly  the  steep-sided  knobs 
(nunataks)  which  are  found  to  characterize  the  relatively 


74 


CHAEACTERISTICS  OF  EXISTING  GLACIERS 


FIG.  35  a.  —  Characteristic  surface  con- 
tours in  Eastern  Swedish  Lapland  due 
to  sculpturing  by  continental  and  moun- 
tain glaciers. 

6.  Horizon  line  showing  the  modifica- 
tion of  surface  moulded  by  continental 
glaciers,  through  the  later  work  of  slug- 
gish mountain  glaciers.  The  deep  ' '  bite 
in  the  horizon  line  is  the  famous  Lapp's 
Gate. 

c.  Flat  U-channel  on  plateau  of  West- 
ern Norway;    Geirangerfjord. 

d.  A  steep  rock  knob  rising  from  the 
plateau  of  Norway ;    Oxenelvene  on  the 
Nordfjord. 


low  surfaces  of  Swedish 
Lapland  are  here  to  be  seen 
rising  out  of  the  level  of  the 
plateau  (see  Fig.  35  d). 

In  these  sections  of  Scan- 
dinavia, the  problems  of 
glacial  sculpture  are  much 
more  complex,  and  are  not 
to  be  solved  by  considera- 
tion of  the  latest  glaciation 
only.  As  is  now  well  recog- 
nized, the  Pleistocene  glaci- 
ation consisted  of  some 
four  distinct  glacial  cycles, 
separated  by  inter-glacial 
^ periods  which  were  charac- 
terized by  relatively  mild 
climatic  conditions.  An 
earlier  submergence  of  the 
coast  regions  (see  plate  17, 
B)  has  been  followed  by 
large  and  rapid  uplifts,  so 
that  former  strand  lines  are 
now  to  be  seen  high  up 
upon  the  shores.  Of  the 
origin  of  the  fjords  —  the 
deep  and  now  partially 
submerged  U  -valleys  —  we 
know  at  least  that  their 
present  form  was  given 
them  when  they  were  occu- 
pied by  glacier  streams;3 
and  their  definitely  oriented 
arrangement  further  be- 


HIGH  LATITUDE  GLACIAL  SCULPTURE 


75 


trays  the  fact  that  the  glacial  excavation  exercised  a  selec- 
tive process  on  the  lines  of  preexisting  fractures  within  the 
rocky  basement,  guided,  perhaps,  on  these  lines  by  earlier 
rivers  which  had  first  discovered  these  special  lines  of  weak- 
ness within  the  earth's  surface  shell  (see  Fig.  36). 


FIG.  36.  —  Map  of  the  vicinity  of  the  Storf  jord  in  Norway,  showing  the  regular 
arrangement  of  the  fjords  and  submerged  valleys  in  three  principal  parallel 
series  separated  by  sub-equal  space  intervals. 

The  Rock  Pedestals  bounded  by  Fjords.  — The  late  uplift  of 
the  coast  subsequent  to  the  formation  of  these  deep  fjords 
has  raised  veritable  pedestals  of  rock  surmounted  by  rela- 
tively flat  surfaces,  on  which  are  revealed  under  exceptional 
circumstances  the  characteristic  subdued  forms  found  in  the 
lower  country  of  Northern  Lapland  (see  Fig.  32,  p.  71). 
Since  these  pedestals  now  lift  their  heads  above  the  snow-line 
of  the  region,  ice-caps  are  amply  nourished  upon  them,  so  as 
often  to  more  than  cover  the  surface  and  spill  over  the  edges 
wherever  the  margin  has  been  notched  by  the  earlier  sculp- 
turing. Near  the  centre  of  the  pedestal  the  process  of  sub- 
glacial  abrasion  pares  down  the  inherited  irregularities, 


76 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


whereas  near  the  margins  where  the  ice  is  thinner  and  the 
gradients  are  steeper,  the  inherited  knobs  have  been  greatly 


FIG.  36  a.  —  Nunataks  rising  out  of  the  surface  of  the  Folgefond,  an  ice-cap  of 

Southern  Norway. 

increased  in  height.     Such  a  knob  enveloped  in  the  marginal 
portion  of  a  Norwegian  ice-cap  is  reproduced  in  plate  17  A 


FIG.  37.  —  Erosional  surface  left  within  the  marginal  zone  of  a  Norwegian  ice- 
cap. The  smoothly  domed  floor  and  the  steep  projecting  knobs  are  characteris- 
tic. A  moraine  is  in  the  foreground. 


PLATE  17. 


A.    The  Hardangerjokull,    a   plateau   glacier   of  Southern   Norway,  where  at   its 
margin  is  seen  the  Kongsnut  nunatak. 


B.    Upland  sculptured  by  mountain  glaciers  and  partially  submerged  through  de- 
pression.    Part  of  one  of  the  Lofoten  Islands. 

(From  a  photograph  by  Dr.  L.  M.  Hollander.) 


HIGH  LATITUDE  GLACIAL  SCULPTURE 


77 


and  others  appear  in  Fig.  36  a.     Figure  37  shows,  on  the 
other  hand,  the  site  of  such  a  margin  to  an  ice-cap,  after  the 


FIG.  38.  —  View  of  the  Seven  Sisters  in  Northwestern  Norway,  a  series  of  ice-cap 
nunataks  sharpened  by  the  overflow  of  the  glacier  streams  at  the  margin. 

ice  has  retired.  Here  we  find  a  smoothly  polished  surface 
descending  on  low  gradients  toward  the  margin  of  the  ped- 
estal. From  this  gently  domed  surface  rise  numerous  knobs 


FIG.  39.  —  Broad  glacial  trough  overdeepened  by  the  overflow  glacier  of  later  ice- 
cap. 

of  rock,  the  marginal  nunataks,  though  here  the  ice  has  not 
reached  the  margin  of  the  pedestal  so  as  to  descend  into  the 


78 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


surrounding  fjords.  (See  pi.  34  A.)  In  Fig.  38  is  seen 
another  example  where  the  ice  has  spread  over  the  edge  of 
its  base  and  has  deepened  and  widened  the  troughs  upon  its 
margins,  thereby  sharpening  the  intervening  knobs. 


FIG.  40.  —  Circular  tind  with  acute  apex  from  the  Lofoten  Islands.      The  Ten- 
naes  Tind,  Kirkefjord  (after  a  photograph  by  Dr.  L.  M.  Hollander). 

The  Norwegian  Tind.  —  Where  the  overflow  streams  on 
the  margin  of  the  ice-cap  are  of  notably  smaller  dimensions 


PLATE  18. 


A.  The  Fjaerlandsfjord  on  the  margin  of  the  Jostedalsbraen,  showing  the  nu- 
nataks  inherited  from  an  earlier  cycle  as  they  develop  into  tinds  by  the  over- 
flow ice  streams  deepening  the  channels  which  separate  them. 


B.    Nykerne,   Vesteraalen.      Typical  tinds   formed  on    the  margin  of   Norwegian 
plateau  glaciers.     A  later  product  of  the  process  shown  above,  in  A. 


HIGH  LATITUDE  GLACIAL  SCULPTURE  79 

than  their  predecessors  of  an  earlier  cycle  a  sharp  shoulder 
has  developed  on  either  side  of  the  valley  (see  Fig.  39). 
The  deepening  of  the  channels  of  small  overflow  glacier 
streams,  if  continued,  so  lowers  the  marginal  channels  as  to 
transform  the  inherited  nunataks  into  high  peaks  sometimes 
having  the  form  of  bee-hives,  on  which  the  sharp  change  in 
slope  marking  the  transition  from  the  earlier  to  the  later 
sculpture  can  often  be  made  out.  In  plate  18  A  an  existing 
Norwegian  glacier  is  seen  modifying  the  nunataks  in  this  man- 
ner, while  in  B  of  the  same  plate  the  later  effect  of  the  process 
is  to  be  observed.  These  steep  rounded  peaks  are  the  character- 
istic tinds  of  the  Norwegian  coast.  They  are  markedly  circular 
at  their  base,  they  rise  at  first  on  excessively  steep  slopes,  but 
at  greater  heights  take  on  gentler  gradients,  often  showing 
a  sharp  change  in  curvature,  as  is  indicated  in  plates  18  B 
and  34  B. 

In  the  Lofoten  Islands,  a  western  outlier  of  the  Norwe- 
gian plateau  to  the  north  of  the  Arctic  circle,  tinds  have  de- 
veloped apparently  by  this  process,  though  they  have  here 
taken  a  sharply  conical  form  with  almost  circular  base,  so 
that  they  resemble  in  form  the  point  of  a  well-sharpened  pen- 
cil (see  Fig.  40).  Inasmuch  as  these  develop  in  a  massive 


SNOW  CAP  SNOW  CAP 


FIG.  41.  —  Successive  diagrams  to  illustrate  a  theory  of   the  shaping  of  acute 
circular  tinds  through  exfoliation. 

igneous  rock,  a  gabbro,  and  the  surfaces  indicate  clearly  that 
the  forms  are  now  being  shaped  as  a  result  of  heavy  exfolia- 
tion, a  suggestion  may  be  hazarded  with  regard  to  the  latest 


80          CHARACTERISTICS  OF  EXISTING  GLACIERS 

stages  of  their  evolution.  A  tind  shaped  by  overdeepening 
on  the  margin  of  an  ice-cap  (see  plate  18  B  and  Fig.  41)  is 
by  reason  of  its  steep  sides  able  to  support  snow  only  upon  its 
summit.  About  its  flanks  the  tind  is  scaled  off  and  rendered 
circular  in  plan.  The  protecting  snow-cap4  prevents  this  ac- 
tion at  the  top,  but  this  cap  is  melted  at  its  margin  where 
warmed  by  radiation  from  the  neighboring  rock  surface. 
The  water  derived  from  this  melting  enters  all  cracks  due  to 
exfoliation,  thus  greatly  facilitating  the  process  and  prevent- 
ing the  formation  of  an  overhanging  rock  cornice.  The 
stages  of  the  process  are  suggested  in  the  diagrams  of  Fig.  41. 

REFERENCES 

1H.  W.  Feilden,  "Notes  on  the  glacial  geology  of  Arctic  Europe  and 
its  Islands,"  Part  II,  Quart.  Jour.  Geol  Soc.,  vol.  52,  1896,  p.  726. 

2  The  italics  are  mine.  —  W.  H.  H. 

3  Fr.  MachaSek,  "  Geomorphologische  Studien  aus  dem  norwegischen 
Hochgebirge,"  Abh.  d.  k.  k.  geogr.  Gesellsch.  in  Wien,  vol.  7,  1908,  pp.  1- 
61,  11  pis.  and  a  map. 

4  In  the  long  winter  season. 


CHAPTER  VI 

GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION 

Abandoned  Moraines  of  Mountain  Glaciers. — Not  only  do 
we  find  in  valleys  the  marks  of  former  occupation  by  moun- 
tain glaciers  in  characteristic  erosional  forms  —  the  cirque, 
the  roches  moutonnees,  the  U -valley,  and  the  hanging  side  val- 
ley —  but  in  many  cases,  at  least,  the  evidence  is  supported 
by  characteristic  glacial  deposits.  These  deposits  are  natu- 
rally less  in  evidence  in  the  higher  levels,  where  erosion  has 
been  more  active ;  but  toward  the  lower  reaches  the  impor- 
tance of  glacial  deposits  rapidly  increases.  With  the  retire- 
ment of  the  glacier  up  its  valley,  medial  and  ground  moraines 
come  alike  to  occupy  the  valley  floor,  though  the  talus  and 
landslide  conspire  to  cover  the  lateral  portions  from  sight. 


FIG.  42.  —  Terminal  and  lateral  moraines  remaining  from  earlier  mountain  glaciers 
which  pushed  out  upon  the  flanks  of  the  Sawatch  range  (after  W.  H.  Holmes). 

Wherever  the  glaciers  have  pushed  out  upon  the  foreland,  and 
there  been  halted  for  considerable  periods,  the  lateral  and 
terminal  moraines  have  been  left  as  definite  and  often  well 
marked  topographic  features  (see  Fig.  42).  Such  terminal 

G  81 


82 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


moraines  at  the  mountain  front  sometimes  show  the  con- 
tours of  the  expanded  foot,  and 
quite  generally  also  the  first  series 
of  recessional  moraines  (see  Fig. 
43  and  plate  15). 

Within  the  valleys  and  back 
from  the  front  of  the  range, 
glaciers  have  also  left  behind 
them  series  of  recessional  termi- 
nal moraines  to  mark  the  princi- 
pal halting  places  during  their 
retreat.  These  moraines  in  many 
cases  hold  back  the  water  of  the 
Bailey  stream,  forming  morainal 
of  Little  Cottonwood  canyon  lakes,  as,  for  example,  in  Parker 

of   the   Wasatch   range    (after      ^  /•     J.T          cc  TVT  i 

Canyon  of  the  Sierra  Nevadas 
(see  plate  15),  or  Convict  Lake 
within  the  same  general  region 


FIG.  44.  —  Convict  Lake,  a  lake  behind  a  morainal  dam  in  a  glaciated  valley  of  the 
Sierra  Nevadas  in  California  (after  a  photograph  by  Fairbanks). 


GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION     83 


The  Tongue-like  Basin  before  the  Mountain   Front.  — 

Wherever  with  ampler  nourishment  glaciers  have  coalesced 
and  expanded  to  the  proportions  of  the  piedmont  type,  the 
marginal  moraine  has  acquired  formidable  dimensions  and 
may  be  miles  in  width,  and  of  considerable  height.1  The 
width  of  this  ice  deposit  is  extended  toward  the  interior 
of  the  ice-apron  by  a  zone  of  drumlins  —  cigar-shaped 
hills  of  till  whose  longer  axes  are  perpendicular  to  the  mo- 
raine.2 Thus  is  built  up  a  tongue-like  basin  often  with  sub- 
ordinate marginal  lobes,  within  which  the  glacier-apron  rested 
(Zungenbecken  of  Penck).  Such  a  basin  is  shown  in  Fig. 
49,  p.  88. 

Border  Lakes.  —  The  study  of  the  glaciers  which  in  Pleis- 
tocene times  pushed  out  from  the  portals  of  the  Alps  upon  the 


FIG.  45.  —  Map  of  the  moraines  and  drumlins  within  and  about  the  apron  of  the 
piedmont  glacier  of  the  Upper  Rhine  (after  Penck  and  Bruckner). 

Swiss  and  Italian  forelands,  has  proved  most  illuminating. 
In  Fig.  45  is  reproduced  a  map  of  the  moraines  formed  about 
the  apron  of  the  great  piedmont  glacier  which  once  occupied 


84 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


the  valley  of  the  Upper  Rhine  and  a  portion  of  its  foreland. 
The  central  area  of  this  basin  is  now  occupied  by  the  beautiful 
Lake  Constance,  which  in  an  earlier  and  higher  stage  ex- 
tended past  the  border  of  the  foot-hills  into  the  Alpine  valley. 

Such  lakes. are 
found  in  many 
similar  sites  of 
piedmont  ice- 
aprons  on  the 
borders  of  the 
Alps,  and  have 
been  referred 
to  as  border 
lakes  (Rand- 
seen).  Heavy 
morainic  accu- 
mulations hem 
them  in  upon 
the  outer  mar- 
gin, and  their 
waves  lap  the 
rising  slope  of 
the  glacier  val- 
ley within  its 
gateway.  An 
instance  in 
which  the  plan 
of  the  lake 

brings  out  with  especial  clearness  the  relatively  narrow 
valley  and  the  expanded  form  of  the  ice-apron  without, 
is  Lake  Garda  (see  Fig.  46).  Geologically  considered,  lakes 
are,  however,  notoriously  short-lived,  and  the  basins  of 
extinct  lakes  are  found  at  the  portals  of  most  of  the  larger 
Alpine  valleys  which  have  not  existing  lakes.3  The  con- 


FIG.  46.  —  Lake  Garda  in  a  southern  gateway  to  the  Alpine 
highland  expanded  over  the  apron  site  of  the  earlier  pied- 
mont glacier  (after  Penck  and  Bruckner). 


GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION      85 

ditions  on  the  northern  border  of  the  Alps   are  brought 
out  in  Fig.  47. 


FIG.  47.  —  Outline  map  of  the  northern  border  of  the  Alpine  highland  showing  the 
basins  of  former  lakes.  The  trumpet-like  widening  of  the  valleys  at  their 
mouths  should  be  especially  noted  (based  on  a  map  by  Bruckner). 

Tongue-like  basin  lakes  within  the  apron  site  of  former 
piedmont  glaciers  would  appear  to  have  been  characteristic 
also  of  the  piedmont  glaciation  in  the  northern  Rocky  moun- 
tains of  Montana.4 

Stream  Action  on  the  Mountain  Foreland. — Wherever 
glaciers  are  so  large  as  to  expand  upon  the  foreland  to  the 
range  which  furnishes  their  nourishment,  they  build  up,  as 
has  been  seen,  a  broad  rampart  of  morainic  rock  debris 
which  later  marks  the  limit  of  their  advance.  The  con- 
stancy of  occurrence  and  the  magnitude  of  these  deposits 
from  the  ice  near  its  margin,  testify  to  the  gradual  change 
from  increasing  rigor  of  climate  to  a  progressive  amelioration 
of  these  conditions.  No  less  significant  in  this  respect  are 
the  heavy  deposits  which  outside  the  marginal  moraine  have 
been  distributed  by  streams  of  water  from  the  glacier. 

Most  of  this  water  emerges  from  beneath  the  ice,  though 
much  of  it  may  have  flowed  upon  the  glacier  surface  for 
greater  or  less  distances  until  permitted  to  descend  through 
crevasses  to  the  bottom.  Russell's  study  of  the  Malaspina 
glacier  of  Alaska,  the  one  existing  example  of  a  piedmont 


86  CHARACTERISTICS  OF  EXISTING  GLACIERS 

glacier  that  has  been  carefully  studied,  showed  that  streams 
of  water  from  near  the  upper  edge  of  the  ice-apron  there 


SCALE  :  1  in.  =  1£  mi. 

FIG.  48.  —  A  braided  stream  which  flows  from  the  margin  of  the  Vatnajokull  in 
Iceland.     (From  the  new  map  by  the  Danish  General  Staff,  1905.) 


GLACIAL  FEATURES   DUE  MAINLY  TO   DEPOSITION      87 

disappeared  into  tunnels  within  the  ice  to  be  lost  to  sight 
until  their  reappearance  at  the  outer  margin. 

The  water  of  these  streams  is  in  the  lower  levels  held 
within  the  ice  as  within  a  pipe,  and  is  in  consequence  under 
strong  hydrostatic  pressure.  Its  flow  is,  therefore,  much 
more  rapid  than  would  be  the  case  with  a  liquid  having  a 
free  surface.  In  fact,  it  could  not  otherwise  ascend  the  slope 
which  we  have  found  to  be  characteristic  of  the  outer  portion 
of  the  tongue-like  basin  beneath  the  ice-apron. 

The  Outwash  Apron.  — Emerging  from  beneath  the  ice,  the 
flow  is  suddenly  checked  and  the  stream  being  overloaded 
with  rock  debris,  this  is  quickly  deposited  as  sediment,  the 
coarser  materials  nearer  the  ice  margin  and  the  finer  ones 
at  greater  distances.  Thus  is  built  up  a  broadly  extended 
outwardly  sloping  platform  composed  of  water-deposited 
materials,  which  platform  surrounds  the  glacier  and  its 
marginal  moraine  as  an  outwash  plain  or  outwash  apron. 

Over  the  nearly  level  surface  of  the  outwash  apron,  the 
streams  flow  in  ever  shifting  serpentine  courses,  and  are 
joined  to  their  neighbors  on  either  side  only  to  divide  the 
waters  of  the  combined  streams  at  the  first  minor  obstruction 
that  is  encountered.  Such  composite  streams  may  be 
compared  to  the  strands  of  a  braid,  and  they  have  been  de- 
scribed as  " braided  streams"  (see  Fig.  48).  The  width  of 
such  a  stream,  or  perhaps  better,  series  of  streams,  may 
be  as  great  or  even  greater  than  the  individual  length.  Con- 
stantly shifting  their  courses  through  lateral  migrations, 
such  rivers  grade  the  plain  on  which  they  flow  to  the  even- 
ness of  a  well-sanded  floor.  This  peculiarity  and  their 
location  just  without  a  marginal  moraine  (see  Fig.  49) 
make  the  later  determination  of  such  plains  a  relatively 
easy  matter. 

Eskers  and  Recessional  Moraines.  —  To  indicate  their  re- 
lation to  glaciers  as  well  as  to  describe  their  deposition  by 


88          CHARACTERISTICS  OF  EXISTING  GLACIERS 

streams,  out  wash  deposits  are  referred  to  as  "  fluvio-glacial." 
They  are  sands  and  gravels  imperfectly  stratified  and  hav- 
ing included  lenticular  masses  of  coarser  and  finer  materials. 


M 


FIG.  49.  —  Ideal  form  of  a  tongue-like  basin  remaining  on  the  site  of  the  ice  apron 
of  a  piedmont  glacier  and  surrounded  by  the  outwash  apron.  M,  marginal 
moraine  at  outer  limit  of  ice  advance ;  D,  drumlins ;  C,  basin  usually  occupied 
by  lake ;  T,  outwash  plain  of  fluvio-glacial  deposits  (after  Penck). 

Russell  has  described  streams  which  issue  from  the  margin 
of  the  Malaspina  glacier  with  such  velocity  that  the  sudden 
checking  of  their  current  causes  the  deposit  of  relatively 
coarse  materials  in  a  steep  apron  resembling  in  form  the  dry 
deltas  of  mountain  fronts  within  semi-arid  regions.  He 
points  out  that  a  continuance  of  such  streams  during  a  reces- 
sion of  the  glacier  would  build  up  a  serpentine  ridge  of  water- 
deposited  materials  whose  average  course  would  be  per- 
pendicular to  the  marginal  moraine.5  Such  ridges,  known  as 
"eskers,"  have  not  been  reported  from  the  sites  of  the  Alpine 
piedmont  aprons,6  though  they  appear  to  have  formed 
under  somewhat  similar  conditions  along  the  east  front  of 
the  Rocky  mountains  in  Montana.7 

It  should  not  be  overlooked  that  while  Russell's  obser- 
vations make  it  probable  that  eskers  are  now  forming  in 
the  tunnels  beneath  the  ice  apron  and  behind  the  alluvial 
fans  which  block  their  outlets,  the  eskers  do  not  appear 
outside  the  ice  front.  Tarr,  who  has  confirmed  Russell's 
conclusion,  thinks  that  the  active  stream  erosion  at  the  ice 
front  would  destroy  the  esker  as  fast  as  it  was  uncovered, 
and  that  eskers  have  become  visible  only  where  the  ice 
ended  in  bodies  of  standing  water  or  else  had  become  rela- 


GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION      89 

lively  stagnant.8  The  former  case  would  apply  to  the  osar 
of  Sweden,  and  the  frequent  termination  of  eskers  in  delta- 
like  sand  plains  with  relatively  flat  upper  surface  and 
steeply  sloping  margins,  would  likewise  favor  this  view. 

With  the  commencement  of  the  receding  hemicycle  of 
glaciation,  the  ice  front  retires  from  its  marginal  moraine 
and  eventually  enters  the  mountain  valley,  though  usually 
leaving  behind  it  a  series  of  smaller  and  so-called  "  reces- 
sional moraines  "  to  mark  successive  and  relatively  short 
halting  places  during  its  retreat.  The  uncovered  site  of 
the  former  ice-apron  is,  as  we  have  seen,  a  basin,  so  that 
this  is  filled  with  water  from  the  melting  of  the  ice  during 
the  retreat  to  the  mountain  front.  The  water  thus  im- 
pounded finds  its  outlet  at  the  lowest  level  of  the  morainal 
crest,  and  being  already  filtered  of  coarser  material  by 
the  lake  itself,  this  outlet  rapidly  cuts  a  channel  through 
the  loose  materials  of  the  moraine  and  its  bordering  plain 
of  fluvio-glacial  deposits.  Thus  sections  are  exposed  to 
view  revealing  a  history  of  the  glacier  whose  episodes  are  to 
be  compared  with  those  disclosed  by  the  plan  of  the  valley 
above  when  it  has  likewise  been  laid  bare. 

Stream  Action  within  the  Valley  during  the  Retirement  of 
the  Glacier.  —  The  "glacier  staircase"  left  by  the  ice,  with 
its  rock-basin  lakes  high  up  in  the  valley  and  its  morainal 
lakes  within  the  lower  reaches,  undergoes  a  rapid  transform- 
ation under  the  influence  of  running  water  so  soon  as  the 
ice  has  largely  vacated  the  valley.  Flowing  from  the  waning 
remnant  of  the  glacier,  this  water  is  overburdened  with 
sediment.  Its  current  is  sluggish  over  the  treads  of  the  steps, 
but  develops  cascades  over  the  cliffs  between.  The  coarse 
debris  which  it  carries  is  thus  quickly  dropped  upon  the 
treads  to  fill  the  lake  basins,  and  with  the  aid  of  the  finer 
material  as  tools,  the  rock  obstructions  are  cut  through  in 
narrow  canyons  and  with  a  marvellous  rapidity.  Where  a 


90          CHARACTERISTICS  OF  EXISTING  GLACIERS 

barrier  of  more  resistant  rock  has  hemmed  in  a  portion  of 
the  valley  (Riegel),  narrow  and  picturesque  gorges  have 
been  cut,  such  as  the  Aarschlucht  and  the  gorge  of  the 


FIG.  50.  —  Gorge  of  the  Albula  river,  near  Berkun,  in  the  Engadine. 


GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION     91 

Corner.  Tyndall  has  described  many  of  these  interesting 
gorges  within  the  "European  playground."9  One  of  the 
finest  illustrations  is  furnished  by  the  Albula  River,  near 
Bergun,  in  the  Engadine  (see  Fig.  50).  Here  the  glaciated 
valley  with  its  characteristic  U -section,  is  at  the  top  of  the 
narrow  gorge,  which  latter,  therefore,  represents  the  work 
of  the  stream  since  the  retirement  of  the  glacier. 

Landslides  and  Rock  Streams  within  the  Vacated  Valley. 
—  Perhaps  the  most  general  characteristic  of  regions  which 
have  in  recent  times  been  sculptured  by  mountain  glaciers 
is  the  dominance  of  the  precipitous  rock  face  —  the  walls  of 
the  fretted  upland.  To-day,  wherever  rock  climbing  is 
indulged  in,  there  glaciers  are  to  be  seen,  or  the  evidence 
of  their  former  presence  is  everywhere  overwhelming.  It 
is  the  sapping  process  active  in  cirque  recession  and  in 
valley  widening  which  has  here  developed  the  nearly  ver- 
tical rock  face. 

Obviously  such  steep  surfaces  are  unstable  under  existing 
conditions  of  weathering  within  humid  regions,  and  can 
long  retain  their  forms  only  under  the  most  favorable  cir- 
cumstances. Until  the  glacier  vacated  the  valley,  the  walls 
were  in  part  supported  at  least  toward  the  base  by  the  ice 
itself.  On  the  Vernagt  and  Rhone  glaciers  a  sliding  down 
of  the  walls  has  begun  in  the  parts  but  lately  left  unsup- 
ported.10 If  of  weak  or  porous  materials,  or  if  intersected 
by  many  planes  of  ready  jointing  or  cleavage,  such  precipi- 
tous faces  become  an  easy  prey  to  frostwork  and  rock 
slide.  For  these  reasons,  glaciated  valleys  within  mountain 
districts  have  often  been  the  scenes  of  disasters  from  ava- 
lanche. Wherever  the  rock  is  of  a  porous  nature  or  has 
open  structures,  water  gradually  comes  to  fill  all  the  spaces 
within  the  material,  at  least  along  certain  planes  favorable 
to  its  entry.  After  a  time  prodigious  masses  of  rock  sud- 
denly descend  under  the  influence  of  gravity,  and  within 


92          CHARACTERISTICS  OF  EXISTING  GLACIERS 

the  space  of  a  few  seconds,  or  at  most  minutes,  they  have 
either  partially  or  wholly  blocked  the  valley,  leaving  great 
scars  to  mark  their  former  positions. 

The  landslide  of  Frank,  Alberta,  which  occurred  in  1903, 
near  where  the  southern  line  of  the  Canadian  Pacific  Rail- 
road enters  the  Crows7  Nest  Pass  of  the  Rocky  Mountains, 
was  the  movement  of  a  mass  of  loose  earth  a  half  mile  square 
and  between  400  and  500  feet  in  thickness.  Only  about 
a  minute  and  a  half  after  this  mass  started  from  a  shoulder 
of  Turtle  Mountain,  it  had  travelled  two  miles  and  a  half 
and  been  spread  over  a  square  mile  of  valley  bottom.11 
Farther  south  in  the  Rocky  Mountains,  and  in  Colorado 
particularly,  are  numerous  relics  of  former  great  slides.12 
Here  the  insecure  foundations  of  massive  rocks  and  a 
jointed  and  shattered  condition  of  these  rocks  themselves 
has  facilitated  the  entrance  of  water  within  the  rock 
mass  and  greatly  promoted  avalanching. 


FIG.  51.  —  Ideal  section  showing  successive  slides  from  a  canyon  wall  producing 
a  staircase  effect  with  back-tilted  treads  (after  Russell). 

How  important  the  vertical  joint  planes  may  be  in  the 
settling  away  and  eventual  fall  of  the  valley  walls  is  shown 
to  advantage  in  the  Otzthal  of  Switzerland,  where,  in  the 
angle  between  the  Vernagthal  and  the  Rosenthal  a  little 
above  the  height  of  the  glacier  surface  at  its  maximum, 
the  wall  is  now  settling  down  in  sections  separated  by  joint 
planes  so  as  to  produce  the  form  of  a  staircase.13  These 
conditions  are,  moreover,  common  to  all  high  vertical  cliffs, 
and  Russell  long  ago  pointed  out  that  successive  slides 
take  place  from  steep  canyon  walls  in  such  a  manner  as  to 


GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION     93 

produce  a  staircase  effect  with  back-tilted  treads  (see  Fig. 
51).14 

From  the  glacial  valleys  of  Switzerland  many  examples 
of  great  landslides  have  been  supplied.  In  1881  the  town 
of  Elm  in  Canton  Glarus  was  overtaken  by  a  slide  from  the 
Plattenbergkopf,  which  had  been  partly  undermined  in  a 
slate  quarry.  About  twelve  million  cubic  yards  of  rock  fell 
a  distance  of  about  1500  feet,  shot  across  the  valley  and  up 
the  opposite  slope  to  a  height  of  300  feet,  and  being  there 
deflected  spread  over  a  broad  plain  in  a  sheet  which  had  an 
area  of  a  million  square  yards.  Over  the  range  from  Elm 


FIG.  52. —  View  of  the  succession  of  rock  slides  from  the  north  wall  of  the  Upper 
Rhine  near  the  town  of  Flims. 

and  above  the  town  of  Chur  in  the  valley  of  the  Upper  Rhine 
is  the  site  of  a  veritable  succession  of  slides  from  the  valley 
wall,  known  far  and  wide  as  the  Flimser  Bergsturz  (see  Fig. 
52). 

Many  of  the  apparent  steps  in  the  transverse  sections  of 
Alpine  valleys15  are  to  be  explained  through  landslides  of 
this  nature. 


94          CHARACTERISTICS  OF  EXISTING  GLACIERS 

Rock  Flows  from  Abandoned  Cirques.  —  Long  after  the 
waning  horseshoe  glaciers  have  disappeared  from  glacial 
amphitheatres,  the  winter  snows  will  there  be  collected  and 
persist  through  a  portion,  at  least,  of  the  summer  season. 
The  same  conditions  of  excessive  frost  weathering,  which  we 
have  become  familiar  with  in  the  process  of  nivation  and 
of  cirque  recession  within  the  same  levels  must,  therefore, 
long  continue  to  exist.  Essentially  the  same  conditions 
may  be  said  to  be  characteristic  of  those  other  and  vaster 
inhospitable  areas  of  the  sub-polar  regions  which  are  un- 
covered by  ice  and  have  but  a  thin  covering  only  of  snow. 
For  these  districts  the  mechanical  process  of  rock  rending 
and  comminution  is  as  characteristic  as  the  chemical  process 
of  decomposition  within  a  warmer  humid  region. 

After  the  rending  of  the  rock  materials  has  been 
accomplished,  gravity  becomes  effective  to  bring  about  a 
transfer  of  material  to  the  lower  levels  by  a  process  of  rock 
flow  which  has  been  called  "solifluction."16  To  this  flow  of 
rock  debris  belong  many  of  the  properties  either  of  water  or 
of  ice-streams,  and  the  moving  masses  have  in  different  dis- 
tricts been  called  "  mud  rivers/'  "  stone  rivers/7  "  rock 
flows/7  "  rock  glaciers/7  etc.  Together  with  this  flow  goes 
also,  under  certain  conditions,  a  peculiar  striping  of  the  sur- 
face of  the  ground,17  and  as  this  occurs  only  below  a  drift 
of  snow,  the  function  of  the  thaw  water  in  giving  the  mass 
its  property  of  flow  is  at  once  apparent.  It  is  well  to  empha- 
size, then,  that  the  thaw  water  from  the  melting  snowdrift 
determines  both  the  nightly  freezing  and  rending  of  the  rock, 
and  the  fluxion  of  the  rock  mass  as  well. 

Outside  the  inhospitable  sub-polar  regions  it  is  the  aban- 
doned glacier  cirques  which,  largely  because  of  their  high 
altitude  and  their  peculiar  form,  best  supply  the  conditions 
requisite  to  solifluction.  Within  the  San  Juan  Mountains 
of  Colorado,  the  high  glacial  cirques  are  many  of  them  occu- 


GLACIAL  FEATURES  DUE  MAINLY  TO  DEPOSITION     95 

pied  by  somewhat  remarkable  rock  streams.18  The  position 
of  two  of  these  rock  streams  relative  to  the  neighboring 
cirque  walls  is  brought  out  in  Fig.  53  and  in  plate  19,  A 


45*30" 


|Q7°44' 


Contour  interval  SOfeet 

FIG.   53.  —  Map   of  two  high   glacial   cirques   now  partially  occupied   by  rock 

streams.     The  dotted  areas  are  rock  streams  (after  Howe). 

and  B.    The  rocks  are  here,  by  reason  of  their  loose  founda- 
tion, of  their  open  joints,  and  their  steep  forward  grades, 


96          CHARACTERISTICS  OF  EXISTING  GLACIERS 

most  favorable  to  the  entrance  of  water,  and  the  subsequent 
fall  of  the  rock  materials. 

In  the  mountains  of  Alaska  so-called  "  rock  glaciers  " 
occur  which  have  much  in  common  with  the  rock  streams 
of  Colorado.  Rock  glaciers  are  mixtures  of  ice  and  rock, 
sometimes  passing  upward  into  glaciers  of  ice  and  having 
in  lower  levels  a  surface  coating  only  of  angular  rock 
debris.19 

REFERENCES 

1  Russell,  "Malaspina  Glacier,"  Jour.  GeoL,  vol.  1,  1893,  pp.  228-238. 

2Penck  und  Bruckner,  "Die  Alpen  im  Eiszeitalter;''  also  Calhoun, 
I.e.,  Prof.  Pap.  U.  S.  GeoL  Surv.,  No.  50,  p.  20. 

3 Bruckner,  Z.c.,.1909,  p.  793. 

4  Calhoun,  I.e.,  p.  16. 

5 1.  C.  Russell,  "  Glaciers  of  North  America,"  pp.  123-125. 

6Penck  und  Bruckner,  "Die  Alpen  im  Eiszeitalter." 

7  Calhoun,  I.e.,  p.  20. 

8R.  S.  Tarr,  "  Some  phenomena  of  the  glacier  margins  in  the  Yakutak 
Bay  Region,  Alaska,"  Zeit.  f.  Gletscherk.,  vol.  3,  1909,  pp.  96-97. 

9  "Hours  of  Exercise  in  the  Alps,"  pp.  224-230. 

10  Ed.  Bruckner,  "  Die  glazialen  Ziige  im  Antlitz  der  Alpen."  Naturw. 
Wochensch.,  N.  F.,  vol.  8,  1909,  p.  792. 

"  Howe,  Prof.  Pap.  67,  U.  S.  GeoL  Surv.,  1909,  p.  51.  Also  G.  E. 
Mitchell,  Nat.  Geogr.  Mag.,  vol.  21,  1910,  pp.  285-287. 

12  Ernest  Howe,  "  Landslides  in  the  San  Juan  Mountains,"  Prof.  Pap.,  67, 
U.  S.  GeoL  Surv.,  1909,  pp.  1-58. 

13  Bruckner,  "  Die  glazialen  Ziige  im  Antlitz  der  Alpen,"  I.e.,  p.  792. 
See  also  Salisbury,  "Physiography,"  N.  Y.,  1907,  Fig.  98,  p.  108. 

14 1.  C.  Russell,  "Topographic  features  due  to  landslides,"  Pop.  Sci. 
Month.,  vol.  53,  1898,  pp.  480-489. 

15  See  E.  J.  Garwood,  Geogr.  Jour.,  vol.  36,  1910,  p.  320. 

16  J.  G.  Andersson,  "  Solifluction,  a  component  of  sub-aerial  denuda- 
tion," Jour.  GeoL,  vol.  14,  1906,  pp.  91-112. 

17  O.  Nordenskiold,  "  Die  Polarwelt  und  ihre  Nachbarlander,"  1909,  pp. 
60-65.     Wm.  H.  Hobbs,  "Soil  Stripes  in  cold  humid  regions  and  a  kin- 
dred phenomenon,"  12th  Rept.  Mich.  Acad.  Sci.,  1910,  pp.  51-53. 

18  Howe  and  Cross,  "Glacial  phenomena  of  the  San  Juan  mountains, 
Colorado,"  Bull.  GeoL  Soc.  Am.,  vol.  17,   1906,  pp.  251-274.     See  also 
Howe,  I.e.,  pp.  31-55. 

19  Stephen  R.  Capps,  Jr.,  "Rock  Glaciers  in  Alaska,"  Jour.  GeoL,  vol. 
18,  1910,  pp.  359-375,  figs.  1-10. 


PLATE  19. 


A.    Rock  stream  in  a  cirque  on  Greenhalgh  Mountain,  Silverton  quadrangle,  Colo- 
rado (after  Howe,  U.  S.  Geol.  Survey). 


B.    Rock  stream  at  the  head  of  a  cirque  in  the  Silver  Basin,  Silverton  quadrangle, 
Colorado  (after  Howe,  U.  S.  Geol.  Survey). 


PART   II 

ARCTIC  GLACIERS 

CHAPTER  VII 
THE  ARCTIC  GLACIER  TYPE 

Introduction.  —  As  elsewhere  pointed  out,  continental 
glaciers  are  in  other  than  dimensional  respects  sharply 
differentiated  from  those  types  which  have  been  described 
as  mountain  glaciers.1  The  ice-cap  glacier,  while  of  smaller 
dimensions  than  the  true  inland-ice  or  the  continental  glacier, 
is  physiographically  allied  with  this  type,  and  has  few  affini- 
ties with  mountain  glaciers.  The  sharpness  of  the  distinc- 
tion has  often  been  overlooked  for  the  reason  that  true  moun- 
tain glaciers  frequently  exist  within  a  fringe  surrounding  the 
larger  areas  of  inland-ice,  both  in  the  Arctic  and  Antarctic 
regions.  The  distinguishing  difference  between  mountain 
glaciers  and  continental  glaciers  is  one  primarily  dependent 
upon  the  proportion  of  the  land  surface  which  is  left  un- 
covered by  the  ice,  and  the  position  of  this  surface  relative 
to  the  margins  of  the  snow-ice  mass.  With  true  mountain 
glaciers  land  remains  uncovered  above  the  highest  surfaces 
of  the  glacier,  where,  in  consequence,  a  special  erosional  pro- 
cess —  cirque  recession  —  becomes  operative.  The  smaller 
ice-caps  take  their  characteristic  carapace  form  and  cover 
the  surface  of  the  land  within  their  margins,  because  that 
surface  is  relatively  level.  Had  it  been  otherwise,  the  same 
conditions  of  precipitation  would  have  yielded  mountain 
H  97 


98          CHARACTERISTICS  OF  EXISTING  GLACIERS 

glaciers  in  their  place.  The  law  above  stated  is  none  the 
less  applicable,  since,  because  of  this  flat  basement,  no  land 
projects  above  their  higher  levels.2 

There  are,  as  we  shall  see,  other  attributes  which  strikingly 
differentiate  the  large  continental  glaciers  from  all  other 
bodies  of  land  ice.  These  relate  particularly  to  the  nature 
of  the  snow  which  feeds  them,  to  changes  which  that  snow 
undergoes  after  its  fall,  to  the  manner  of  its  transportation, 
etc.  Most  of  these  differences  are  of  such  recent  discovery, 
or  at  least  of  such  recent  introduction  into  the  channels  of 
dissemination  of  science,  that  they  have  not  yet  found  their 
way  to  the  student  of  glacial  geology.  We  shall  profitably 
begin  our  description  of  continental  glaciers  with  the  inter- 
mediate ice-cap  type,  so  as  to  establish  connection  with 
mountain  glaciers  in  the  important  condition  of  alimenta- 
tion. Before  doing  so,  it  will  be  well  to  call  attention  to 
some  contrasts  which  exist  between  the  north  and  south 
polar  regions  in  those  conditions  upon  which  glaciation 
depends. 

North  and  South  Polar  Areas  Contrasted.  —  A  glance  at  a 
globe,  which  sets  forth  the  land  and  water  areas  of  the  earth, 
is  sufficient  to  show  that  the  disposition  of  land  and  water 
about  the  opposite  ends  of  the  earth's  axis  is  essentially 
reciprocal.  About  the  north  pole  we  find  a  polar  sea,  the 
Arctic  ocean,  surrounded  by  an  irregular  chain  of  land 
masses  which  is  broken  at  two  points,  nearly  diametrically 
opposite.  In  the  Antarctic  region,  on  the  contrary,  it  is  a 
high  continent  which  is  massed  near  the  pole,  and  this  is 
bounded  on  all  sides  by  a  sea  in  which  are  joined  all  the 
great  oceans  of  the  globe  save  only  the  Arctic.  This  polar 
continent  is  deeply  indented  on  two  nearly  opposite  margins, 
but  to  what  extent  is  not  yet  known.  The  margins  of  the 
continent  are  extended  beneath  the  sea  in  a  wide  conti- 
nental shelf  or  platform.  The  broad  encircling  ocean, 


THE  ARCTIC  GLACIER  TYPE  99 

while  to  some  extent  invaded  by  the  southern  land  tongues 
of  South  America,  Africa,  Australia,  and  New  Zealand,  is 
yet  so  little  occupied  by  land  masses  that  wind  and  ocean 
currents  are  alike  but  slightly  affected  by  them.  The 
Antarctic  conditions  are,  therefore,  oceanic  —  character- 
ized by  uniformity  and  symmetry  to  a  much  larger  extent 
than  is  true  of  the  northern  polar  region. 

Within  the  northern  hemisphere  a  large  quantity  of  heat 
from  the  tropics  finds  its  way  northward  to  the  breaks  in  the 
northern  land  chain,  through  the  medium  of  great  ocean 
currents  —  the  Gulf  Stream  in  the  Atlantic,  and  the  Japan- 
ese Current  in  the  Pacific.  Cold  return  currents  from  the 
Arctic  region,  and  the  widely  different  specific  heats  of 
land  and  water,  cooperating  with  the  effect  of  the  northward- 
flowing  warmer  currents,  result  in  a  marked  diversity  in 
temperature,  winds,  and  precipitation  at  different  longitudes 
within  the  same  latitudes.  Lack  of  symmetry  in  distribu- 
tion and  wide  variations  in  climatic  conditions  are,  therefore, 
characteristic  of  the  north  polar  region;  and  it  follows  that 
the  present  glaciation  of  the  northern  hemisphere  is  localized 
within  a  few  scattered  areas  where  the  land  projects  far- 
thest toward  the  pole,  and  near  where  there  are  sea  areas  of 
excessive  evaporation  to  supply  the  necessary  moisture. 

The  Fixed  Areas  of  Atmospheric  Depression.  —  Examina- 
tion of  Fig.  54  will  show  that  the  areas  of  existing  heavy 
glaciation  in  the  northern  hemisphere  lie  close  to  the  so- 
called  fixed  areas  of  low  barometric  pressure,  each  of  which 
is  a  long,  curved  trough,  concave  to  the  northward,  one 
central  over  the  Aleutian  Islands'  Arc  at  the  northern 
bight  of  the  Pacific  ocean,  the  other  extending  from  the 
southeastern  extremity  of  Baffin  Land  past  Cape  Farewell, 
and  northeastward  across  Iceland,  so  as  to  occupy  similarly 
the  northern  bay  of  the  Atlantic  ocean.  For  such  northern 
latitudes,  these  areas  of  fixed  low  barometric  pressure  are 


100        CHARACTERISTICS   OF  EXISTING  GLACIERS 

in  consequence  characterized  by  abnormally  large  evapora- 
tion. Wherever  the  moisture-laden  winds  proceeding  from 
these  areas  are  forced  to  rise  by  upland  barriers,  or  to  come 


FIG.  54.  —  Map  showing  the  areas  of  fixed  low  barometric  pressure  in  the  northern 
hemisphere  (after  Buchan).     The  areas  of  heavy  glaciation  have  been  added. 

in  contact  with  cold  rock  or  snow  surfaces,  condensation  and 
precipation  must  inevitably  take  place. 

The  prevailing  westerly  winds  from  the  Pacific,  when  they 
encounter  the  high  backbone  of  the  Cordilleran  System  of 
mountains  in  Alaska  nourish  the  great  mountain  glaciers  of 
that  region.  The  Cordilleras  of  Alaska  are,  however,  compe- 
tent to  arrest  but  a  small  portion  of  these  moisture-laden 
clouds,  for  it  is  only  in  moderate  latitudes  that  they  bar  the 
way,  and  no  highlands  lie  beyond  them  to  the  eastward  until 
the  vicinity  of  Baffin  Bay  has  been  reached. 

On  the  border  of  the  Atlantic  low  pressure  area  are  found 
Greenland,  Iceland,  Spitzbergen,  Norway,  Franz  Josef  Land 
and  Nova  Zembla,  each  with  its  upland  areas  and  its  exist- 


THE  ARCTIC  GLACIEE  TYPE  101 

ing  glaciation.  In  Norway,  Iceland,  and  Franz  Josef  Land 
we  find  ice-caps;  in  Spitzbergen,  Nova  Zembla,  Baffin  Land, 
Grinnell  Land  and  Ellsmere  Land,  the  mantle  of  snow  and  ice 
is  best  described  by  the  name  " inland-ice,"  while  upon  the 
continent  of  Greenland  the  inland-ice  has  continental  dimen- 
sions, and  forms  one  of  the  two  continental  glaciers  that  still 
exist.3 

Of  all  the  northern  ice-sheets,  with  the  exception  of  the  archi- 
pelago of  Franz  Josef  Land,  the  rule  holds  that  they  are  smaller 
than  the  land  masses  upon  which  they  rest,  and  this  in  part  ex- 
presses the  difference  between  the  northern  and  southern 
types  of  inland-ice. 

Ice-caps  of  Norway.  —  In  contrast  with  all  save  the  pied- 
mont type  of  mountain  glaciers,  the  snow-fields  of  ice-caps 


FIG.  55.  —  Idealized   section   showing  the  form  of  "fjeld"   and  "brae"  in  Nor- 
wegian ice-cap. 

are  much  the  larger.  Speaking  broadly,  high  and  relatively 
level  plateaus,  light  winds,  and  low  temperatures  are  favor- 
able to  the  existence  of  ice-caps.  To-day  they  are  not  to  be 
found  in  latitudes  lower  than  60°.  In  Norway,  within  the 
zone  of  heavy  precipitation  along  the  western  coast,  and 
upon  the  remnants  of  the  plateau  separated  by  the  fjords 
are  still  to  be  found  a  number  of  small  ice-caps.  These 
caps  consist  of  a  central  carapace  of  snow  and  ice  from  the 
borders  of  which  narrow  tongues  descend  into  the  fjords. 
The  largest  of  these  ice-caps  is  the  Jostedalsbraen,  having 
an  area  of  1076  square  kilometers.  Whereas  with  moun- 
tain glaciers  the  neve  is  contained  within  a  basin,  the  cirque, 
we  here  find  the  so-called  "  fjeld  "  nearly  level  and  resting 


102'   ^CHARACTERISTICS  OF  EXISTING  GLACIERS 

upon  the  surface  of  the  plateau.  Of  this  fjeld  broadly 
lobate  extensions  lie  upon  its  margin  separated  by  deep 
valleys  or  fjord  heads.  Much  narrower  extensions  of  the 
central  carapace  often  descend  the  steep  slopes  at  the  upper 
end  of  these  valleys  and  may  continue  down  the  valley  floor. 
Their  narrowness  is  largely  explained  by  their  more  rapid 
motion  upon  the  steeper  slope  and  by  the  radiated  heat  from 
the  rock  walls  on  either  side  (see  Fig.  55  and  plate  20)  .4 
Near  the  margins  of  the  ice  carapace,  the  subjacent 
terrane  sometimes  makes  its  appearance  as  rocky  islets  or 
nunataks,  as,  for  example,  in  the  Hardangarjokull  near 
Finse  in  Southern  Norway  (see  plate  17  A). 

Ice-caps  of  Iceland.  —  In  Iceland  are  to  be  seen  some  of 
the  finest  examples  of  ice-caps  that  are  known,  and,  fortu- 


FIG.  56.  —  Maps  of  the  Hofs  Jokull  and  the  Lang  Jokull  (after  Thoroddsen). 

nately,  these  have  been  carefully  studied  by  Thoroddsen.5 
These  ice-caps  form  gently  domed  crests  or  undulating  ice- 
fields situated  upon  the  highest  plateaus  which  rise  above 
the  general  table-land  of  the  country.  Projecting  mountain 
peaks  appear  with  few  exceptions  only  near  the  thinnest 


PLATE  20. 


2000*1000    02  *  e 


»  *  a 


Portion  of  the  new  map  of  the  Jostedalsbriien,  which  displays  the  characteristic  plan  of 
the  surface  physiography.  The  glacier  sends  out  lobes  upon  the  flat  parts  of  the 
spurs  between  fjords,  and  elsewhere  descends  in  long,  narrow  tongues  into  the 
fjords  themselves,  here  dimpled  above  the  fjord  heads  through  indraught  of  the 


THE  ARCTIC  GLACIER  TYPE 


103 


margins  of  the  ice,  where  they  form  either  comb-ridges  or 
sharp  peaks  (see  Figs.  56  and  57).  White  and  altogether 
free  from  surface  rock  debris  except  in  the  vicinity  of  their 
margins,  these  ice-caps  offer  in  this  respect  additional  con- 
trast to  mountain  glaciers.  The  largest  of  the  Iceland  ice- 
caps is  the  Vatna  Jokull,  which  has  an  area  of  8500  square 


FIG.  57.  —  Map  of  the  Vatna  Jokull  (after  Thoroddsen). 


kilometers,  while  the  surfaces  of  the  Hofs  Jokull,  Lang  Jokull, 
and  Myrsdals  Jokull,  each  exceed  a  thousand  square  kilo- 
meters. The  shield-like  boss  of  the  Vatna  Jokull  is  brought 
out  in  the  section  of  Fig.  58. 6 

Those  borders  of  this  ice  mass  which  lie  upon  the  plateau, 
the  northern  and  western  areas,  are  broadly  lobate;  but 
upon  the  southern  and  eastern  margins,  where  the  ice  mass 
descends  to  lower  levels  and  approaches  the  sea,  its  tongues 
sometimes  end  a  few  metres  only  above  sea-level.  It  is 
noteworthy,  however,  that  where  deeply  incised  valleys  in- 
vade the  plateau  upon  this  margin,  the  lobes  of  ice  push  out 
mainly  upon  the  upland  remnants  between  the  valleys, 


104        CHARACTERISTICS   OF  EXISTING  GLACIERS 

though  they  send  narrow  tongues  down  the  valleys  them- 
selves. This,  as  we  shall  see,  is  a  peculiarity  which  ice-caps 
and  the  northern  inland-ice  as  well,  have  in  common  to 
distinguish  them  further  from  mountain  glaciers.  As  was 
found  true  of  the  Norwegian  glaciers,  so  here  the  tongue 
which  follows  the  valley  bottom  and  which  partakes  of  many 
of  the  properties  of  a  mountain  glacier,  is  much  the  narrower.7 
From  comparison  with  the  Antarctic  ice  masses,  these 
rapidly  moving  extensions  of  the  central  mass  through  rock 
gateways  maybe  designated  " outlets "  (see  Part  III,  p.  186). 
This  peculiarity  of  ice-caps  is  well  displayed  upon  the  General 

-2000— i|-r— j — ca.i900m  .  _   , — ^ooo  - 

-1500-1—     ^^^^~  ~~ ~--^^^^^ i  1500  - 

-1000  ris^"^  ^^""^-^ 1-1000- 

-500 — • • — — — X^-— j— 300  - 

Cm  ^s^    0 m 

FIG.  58.  —  Cross  section  of  the  Vatna  Jokull  from  north  to  south  (after  Thoroddsen 

and  Spethmann). 

Staff  Sectional  Map  of  Iceland,  on  scale  1 : 50,000  now  in 
process  of  publication.  The  sections  which  include  the 
Icelandic  ice-caps  show,  not  only  the  contours  of  the  ice 
surface,  but,  further,  the  nature  of  the  crevassing,  and  they 
are  probably  the  finest  glacier  maps  which  have  thus  far 
been  issued.  Plate  21  reproduces  on  a  reduced  scale,  a 
portion  of  section  Oraefajokull. 

From  the  north  or  plateau  margin  of  the  Vatnajokull,  flow 
mighty  but  sluggish  streams  which,  near  the  glacier,  are 
braided  into  constantly  shifting  channels  within  a  broad 
zone  of  quicksand.  In  this  sand,  horse  and  rider,  if  once 
entangled,  are  quickly  lost.  Upon  the  south  margin,  on  the 
other  hand,  the  streams  from  the  melting  of  the  ice  flow  as 
series  of  fast  rushing  rivers,  sometimes  so  broad  as  not  to  be 
bridged,  and  in  these  cases  setting  up  impassable  barriers 
between  districts  (see  Fig.  48,  p.  86). 

Icelandic  ice-caps  differ  from  all  well-known  glaciers  at 


PLATE  21. 


Map  of  the  margin  of  an  Icelandic  ice-cap.  The  tongue-like  streams  of  ice  in  val- 
leys and  the  apron-like  extensions  on  the  plateau  level  are  shown  (from  the  Gen- 
eral Staff  map,  section  Oraefajokull,  1905).  The  north  side  is  here  at  the  bottom 
of  the  map. 


THE  ARCTIC  GLACIER  TYPE  105 

least  in  this,  that  nowhere  else  are  large  ice  masses  in  such 
direct  association  with  so  active  volcanoes.  The  jokulhlaup, 
which  is  the  Icelandic  name  applied  to  one  of  the  charac- 
teristic catastrophies  of  the  island,  occurs  whenever  a  volcano, 
either  visible  in  the  neighborhood  of  the  glacier  or  hidden 
beneath  it,  breaks  suddenly  into  eruption.  The  first  inti- 
mation that  such  an  event  is  transpiring,  is  often  the  drying 
up  of  a  stream  which  flows  from  the  affected  region.  Some- 
times the  people  are  permitted  to  see  great  masses  of  lava 
and  volcanic  ash  issue  together  from  the  glacier.  All  at 
once,  the  stream  which  had  first  dried  up  comes  rushing  down 
its  valley  as  a  foaming  flood  of  water,  spreading  out  for 
miles  and  having  a  depth  sometimes  as  great  as  100  feet. 
The  entire  plain  is  then  spread  with  mud  and  sown  with 
great  rocks  and  also  with  ice  blocks,  some  of  which  are  as 
large  as  the  native  houses.  These  ice  blocks  are  often  buried 
in  the  mud,  and  later,  when  they  have  melted,  they  leave 
deep  pits  in  the  plain  similar  to,  though  smaller  than,  the 
depressions  in  a  "  pitted  plain  "  from  the  continental  glaciers 
of  Pleistocene  time.  The  "  glacier  run  "  of  1903  produced 
pits  (Solle)  in  the  Skeithardr  Sander.  In  1904  the  par- 
tially melted  blocks  of  ice  were  to  be  seen  in  the  pits.8  It 
is  not,  of  course,  here  assumed  that  the  cause  of  the  pits 
of  the  Pleistocene  sand  plains  are  in  any  way  connected 
with  volcanic  action,  but  only  with  the  burial  of  ice  blocks 
under  rock  debris.  Tarr  has  described  the  formation  of 
such  plains  in  front  of  the  Hidden  glacier  of  Alaska,  where 
the  melting  ice  margin  is  becoming  buried  beneath  its  own 
burden  of  rock  debris  and  is  locally  opened  up  in  pit  lakes.9 
During  a  volcanic  eruption,  water  is  seen  to  shoot  up  from 
the  glacier  in  great  jets,  and  it  has  sometimes  happened 
that  the  entire  ice  mass  of  the  jokull  has  been  shattered,  and  a 
chaotic  mass  of  ice  miles  in  width  has  slipped  resistlessly  down 
the  slopes.  With  the  conclusion  of  the  disturbance,  the  as- 


106        CHARACTERISTICS  OF  EXISTING  GLACIERS 

pect  of  the  entire  district  is  sometimes  found  to  be  utterly 
changed.  All  vegetation  has  been  destroyed,  and  ridges 
which  had  lent  to  the  landscape  its  character  have  vanished, 
so  that  streams  have  lost  their  old  channels  and  entered 
upon  wholly  different  courses.10 

Ice-covered  Archipelago  of  Franz  Josef  Land.  —  The  is- 
lands of  Franz  Josef  Land  in  the  high  latitude  of  80°  and  over, 
with  altitudes  of  2000  to  4000  feet,  and  situated  as  they  are 
on  the  borders  of  an  open  sea,  are  the  most  Arctic  in  their 
aspect  of  all  the  smaller  northern  land  masses.  As  a  conse- 
quence, they  are  with  unimportant  exceptions  completely 
snow-capped,  the  snow-ice  covering  sloping  regularly  into  the 
sea  upon  all  sides.  The  Jackson-Harmsworth11  and  Ziegler12 
expeditions,  following  those  of  Nordenskiold,  Nansen,  the 
Duke  of  the  Abruzzi,  and  others,  have  now  supplied  us  with 
fairly  accurate  maps  of  all  islands  in  the  archipelago.  One 
or  two  of  the  western  islands  alone  show  a  narrow  strip  of  low 
shore  land,  but  with  these  exceptions  all  are  ice  covered  save 
for  small  projecting  peaks  or  plateau  edges  near  the  margins 
(see  Fig.  59).  They  present,  therefore,  a  unique  exception  to 
the  law  which  otherwise  obtains,  that  within  the  northern 
hemisphere  glacial  caps  are  smaller  than  the  land  areas  upon 
which  they  rest.  The  appearance  of  the  island  covers  is 
here,  however,  that  of  neve  of  low  density,  rather  than  of 
compact  glacier  ice. 

Prince  Rudolph  Island,  which  was  the  winter  station  of  the 
Italian  Polar  Expedition,  is  no  doubt  typical  of  most  islands 
in  the  archipelago.  This  land  is  described  by  Due  d' 
Abruzzi13  as  "completely  buried  under  one  immense  glacier, 
which  descends  to  the  sea  in  every  direction  except  at  a 
few  points,  such  as  Cape  Germania,  Cape  Saulen,  Cape 
Fligely,  Cape  Brorok,  Cape  Habermann,  and  Cape  Auk. 
At  some  of  these  points  .  .  .  the  coast  is  almost  perpendic- 
ular, which  prevents  the  ice  from  descending  to  the  sea. 


THE  ARCTIC  GLACIER  TYPE 


107 


FIG.  59.  —  Map  of  the  ice-capped  islands  in  the  eastern  part  of  the  Franz  Josef 
Archipelago  (after  Fiala). 


108        CHARACTERISTICS  OF  EXISTING  GLACIERS 

At  others  .  .  .  the  ice,  stopped  by  a  hollow,  falls  into  the 
sea  on  each  side  of  the  headland,  which  thus  remains  un- 
covered. Moreover,  wherever  the  snow  can  rest,  there  are 
glaciers  which  end  at  the*sea  in  an  ice  cliff,  like  that  formed 
by  the  main  glacier,  so  that  it  can  be  said  that  the  entire  coast, 
with  the  exception  of  a  short  extent  of  strand  near  Teplitz 
bay,  is  formed  by  a  vertical  ice  cliff  "  (see  Fig.  60). 

The  movement  of  the  ice  is  so  slow  that  though  a  line  of 
posts  was  established  for  the  purpose  of  measuring  during  a 


FIG.  60.  —  Typical  ice  cliff  of  the  coast  of   Prince  Rudolph  Island,  Franz  Josef 
Land    (after  the  Duke  of  the  Abruzzi). 

period  of  four  months,  no  movement  could  be  detected. 
Except  near  the  outermost  margin,  there  were  few  crevasses, 
and  these  were  covered  by  snow.  In  summer,  on  days  when 
the  temperature  was  above  the  freezing  point,  the  snow 
thawed  rapidly  so  that  torrents  of  water  flowed  from  the 
glacier  to  the  sea,  hollowing  out  channels,  many  feet  in 
width. 

During  the  stay  of  the  "  Polar  Star  "  near  the  island,  it 
was  noteworthy  that  thaw  and  evaporation  upon  the  island 
exceeded  the  precipitation.  Doubtless  because  of  the  slow 
movement  of  the  ice,  no  icebergs  were  seen  to  form  during 
the  entire  stay. 


THE  ARCTIC   GLACIER  TYPE  109 

The  Smaller  Areas  of  Inland-ice  within  the  Arctic  Regions. 
—  The  ice-cap  of  the  Vatna  Jokull  in  Iceland,  which  is  the 


FIG.  61.  —  Map  of  Nova  Zembla,  showing  the  supposed  area  covered  by  inland-ice 
(from  Andree's  "  Handatlas  "). 

largest  to  which  this  name  has  been  applied,  covers  an  area 
of  8500  square  kilometers.  Ice  carapaces,  which  are  better 
described  as  inland-ice,  since  they  cover  considerable  propor- 


110        CHARACTERISTICS  OF  EXISTING   GLACIERS 

tions  of  the  interiors  of  the  land  areas  upon  which  they  rest, 
occur  to  the  northward  of  the  continent  of  Europe  in  Nova 
Zembla  and  Spitzbergen,  and  in  the  lands  to  the  west  of 
Baffin's  Bay,  known  as  Baffin,  Ellesmere,  and  Grinnell 
lands. 


FIG.  62.  —  Map  of  Spitzbergen,  showing  the  supposed  glacier  areas  (from  Andree's 

"  Handatlas"). 

Nova  Zembla  is  a  long,  narrow  island,  stretching  between 
70°  and  84°  of  north  latitude  (see  Fig.  61).  It  is,  in  reality, 
two  islands  separated  by  a  narrow  strait  near  the  latitude  of 
76°.  The  northern  island,  which  to  the  north  is  a  plateau 
attaining  an  altitude  of  1800  feet,  is  supposed  to  be  in  large 


THE  ARCTIC  GLACIER  TYPE 


111 


part  covered  by  inland-ice,  though  it  has  been  as  yet  but  little 
explored.14 

The  Inland-ice  of  Spitzbergen.  —  The  group  of  islands  to 
which  the  name  Spitzbergen  has  been  applied  lies  between 
the  parallels  of  76°  and  81°  of  north  latitude.  The  surface 
is  generally  mountainous,  the  highest  peaks  rising  to  an  ele- 
vation of  about  5000  feet,  though  the  greater  number  range 
from  2000  to  4000  feet  in  altitude.  The  large  northeastern 
land  mass  is  called  North  East  Land  and  is  covered  with  in- 
land-ice which  was  crossed  by  Nordenskjold  and  Palander  in 


FIG.  63.  —  Inland-ice  of  New  Friesland  as  viewed  from  Hinloopen  Strait   (after 

Conway). 

1873 15  (see  Fig.  62).  New  Friesland,  or  the  northeastern  por- 
tion of  the  main  island,  is  also  covered  by  inland-ice 16  (see 
Fig.  63).  The  southwestern  margin  of  this  inland-ice  was 
somewhat  carefully  mapped  by  Conway  and  Gregory  in 
1896,17  and  as  this  presents  some  interesting  general  features, 
the  map  is  reproduced  in  part  in  Fig.  64. 

In  addition  to  the  lobes  which  push  out  upon  the  crest  of 
the  plateau,  there  is  here  an  expansion  laterally  beyond  the 
main  cap  and  at  lower  levels  in  the  form  of  an  apron  which  is 
called  the  Ivory  Gate  (compare  the  Frederikshaab  Glacier  in 
Fig.  94,  p.  171).  Surrounding  the  inland-ice  to  the  westward 
are  small  ice-caps  resembling  the  fjelds  and  braes  of  Norway, 
and  also  true  mountain  glaciers  whose  cirques  have  shaped 
the  mountains  into  the  sharp  pinnacles  of  comb  ridges.  It 
is  to  these  sharp  peaks  that  Spitzbergen  owes  its  name. 


112        CHARACTERISTICS  OF  EXISTING  GLACIERS 

In  the  year  1890  Gustav  Nordenskjold  made  a  journey  be- 
tween Horn  Sound  and  Bell  Sound  on  the  west  coast,  and 
found  behind  the  sharp  peaks  bordering  the  coast  an  ice  sur- 
face almost  without  crevasses  or  nunataks.18  Upon  the  north- 


FIG.  64.  —  Map  of  the  southwestern  margin  of  an  extension  of  the  inland-ice  of 
New  Friesland  (after  Con  way). 

west  coast  no  sharp  peaks  or  comb  ridges  are  found,  but  there 
is  a  low  plateau  with  deep,  narrow  valleys  similar  to  the  west 
coast  of  Norway,  where  it  reaches  the  sea  near  the  North  Cape. 
All  the  rock  surfaces  are  glaciated. 

The  inland-ice  of  North  East  Land  reaches  the  sea  upon  the 
southern  and  eastern  coasts,  but  is  surrounded  by  a  hem  of 
land  upon  the  north  and  west.  Over  the  surface  of  this  ice 


THE  ARCTIC  GLACIER  TYPE  113 

Nordenskjold  journeyed  in  the  spring  of  1873,  finding  it  to 
be  probably  from  2000  to  3000  feet  in  thickness.  Where  it 
reaches  the  sea  on  the  east  coast  is  a  steep  and  inaccessible 
cliff  of  ice,  one  of  the  largest  in  the  northern  hemisphere.19 
On  the  northern  margin,  however,  the  ice  moves  out  upon  a 
plain  with  its  own  upper  surface  of  gentle  slope,  which  except 
for  the  crevasses,  is  not  difficult  of  ascent.  From  near  this 
northern  border  good  seeing  conditions  enabled  Nordenskj  old 
to  say  that  the  ice  mass  stretched  away  to  the  south  and  west 
without  any  interruption  from  nunataks,  but  rising  with 
great  uniformity  into  the  great  flat  dome  of  its  central  area. 
Over  this  snow  surface  every  puff  of  wind  drove  before 
it  a  stream  of  fine  snow  dust,  which  insinuated  itself  into 
everything  and  was  as  troublesome  as  the  sand  of  a  desert.20 

The  upper  layer  of  the  glacier  was  not  of  ice,  but  consisted 
of  hard,  white,  compacted  snow  which  had  been  smoothed 
and  polished  by  the  abrasion  of  the  wind-driven  snow  dust. 
In  a  depth  of  four  to  six  feet  the  surface  layer  of  compact 
snow  passed  over  into  ice,  first  through  a  layer  of  magnificent 
ice  crystals,  next  to  a  distinctly  granular  ice,  and  finally 
into  a  hard,  coherent  ice  mass  in  which  only  the  numerous 
cavities  filled  with  compressed  air  gave  evidence  of  the 
manner  of  its  formation.  When  the  ice-wall  about  these 
cavities  is  by  melting  made  too  weak  to  sustain  the  pressure 
of  the  air  compressed  within  them,  it  breaks  up  with  a  pecul- 
iar crackling  sound  which  in  summer  is  continually  to  be 
heard  from  the  pieces  of  granular  ice  floating  about  in  the 
fjords. 

"  We  wandered,"  says  Nordenskj  old,  "  over  a  kind  of 
'neve  region,  that  is  to  say,  over  a  part  of  the  glacier  where  the 
surface  is  occupied  by  a  layer  of  snow  which  does  not  melt 
away  during  summer,  whereas  in  Greenland  at  the  beginning 
of  the  month  of  July  the  snow  upon  the  surface  of  the  glacier 
was,  on  the  contrary,  already  nearly  completely  melted.  No 


114        CHARACTERISTICS  OF  EXISTING  GLACIERS 

trace  of  the  glacier  lakes,  the  beautiful  and  abundant  glacier 
streams,  the  fine  waterfalls  and  fountains,  etc.,  which  occur 
everywhere  on  the  Greenland  inland-ice  can  be  observed  here, 
and  the  configuration  of  the  surface  showed  that  such  forms 
never  occur,  or  only  to  a  very  limited  extent.  The  melting 
of  the  snow  clearly  goes  on  in  Spitzbergen  on  too  inconsider- 
able a  scale  for  such  phenomena  to  arise." 

"  The  surface  of  the  snow  was,  as  has  been  already  men- 
tioned, quite  level,  generally  hard  packed  by  the  storms. 


FIG.  65.  —  Camping  place  in  one  of  the  "  canals  "  upon  the  surface  of  the  inland-ice 
of  North  East  Land,  Spitzbergen  (after  Nordenskjold). 

and  completely  glazed  and  polished  by  the  stream  of  snow 
which  even  the  gentlest  breeze  of  wind  carried  forward  along 
the  ground.  This  stream  of  snow,  or  more  correctly  of  air 
mixed  with  snow,  had,  however,  in  the  absence  of  a  downfall, 
and  provided  the  wind  was  not  all  too  violent,  only  a  depth  of 
a  few  feet.  It  threw  fragile  bridges  of  snow  over  the  cre- 
vasses, but  did  not  fill  them;  formed  where  there  were  great 
precipices,  true  snow  cascades;  and  filled  up  in  a  few  minutes 


THE  ARCTIC  GLACIER  TYPE 


115 


FIG.  66.  —  Hypothetical  cross  section  of  a  glacial 
canal  upon  the  inland-ice  of  North  East  Land 
(after  Nordenskjold). 


all  shallow  holes  and  depressions.    Thus,  for  instance,  when 

we  emerged  from  our  tent  in  the  morning,  all  trace  that  the 

snow  had  been  tram- 

pled down  the  evening 

before    had    generally 

disappeared,    and   the 

sledges  were  concealed 

in  a  large  drift."  21 
Of  especial  note  were 

the     great     crevasses 

which  ran  generally  in 

straight  lines  for  long 

distances    in    parallel 

series,  sometimes  two 

intersecting  series  being  observed.     More  remarkable  than 

these,  however,  were  the  so-called  "  canals/  '  which  also  for 

the  most  part  ran  parallel  to  each  other,  and  in  some  cases 

were  only  100  feet  apart.  These 
canals,  which  were  found  in  the 
southeastern  part  of  the  area  near 
Cape  Mohn,  were  in  reality  deep, 
flat-bottomed  troughs  within  the 
ice,  bounded  on  either  side  by 
parallel  and  rectilinear  ice  cliffs, 
and  were  in  places  partially  filled 
by  the  indrifted  snow.  Stretching 
for  long  distances  over  the  snow 
plain,  and  set  so  deeply  that  they 

COuld 


FIG.  eT.-Mapshowingthesup- 

posed  area  of  inland-ice  upon    itOUS  drifting  of  the  SnOW  Supplied 

S±t±££=££  an  incline>  th^  were  utilized  for 

camping  places  (see  Fig.  65). 

Nordenskjold  has  explained  these  canals  as  trough  faults 
within  the  ice,  and  has  assumed  that  this  deformation  was 


116        CHARACTERISTICS  OF  EXISTING  GLACIERS 

due  to  changes  of  volume  incidental  to  extreme  temperature 
range  (see  Fig.  66).  This  explanation  in  temperature  changes 
would  leave  the  absence  of  such  structures  in  other  places- 
wholly  unaccounted  for,  and  we  venture  to  believe  that  a 
recent  trough  faulting  within  the  rock  basement  below  the 
ice,  and  communicated  upward  through  it,  would  furnish  a 
more  reasonable  explanation,  particularly  in  view  of  our  later 
knowledge  of  dislocations  connected  with  earthquake  dis- 
turbances. 

Still  deeper  inbreaks  of  the  ice  were  encountered  within 
the  same  region.     These,  though  deeper,  were  generally  of 


FIG.  68.  —  View  of  the  "  Chinese  Wall  "  surrounding  the  Agassiz  Mer  de  Glace  on 
Grinnell  Land  (after  Greely). 


less  extent,  and  were  designated  by  the  sailors  of  the  party 
"  docks  "  or  "  glacier  docks." 

The  Inland-ice  of  Grinnell,  Ellesmere,  and  Baffin  Lands.  — 
Something  has  been  learned  of  the  inland-ice  of  Grinnell 
Land  (see  Fig.  67)  from  the  report  of  Lieutenant  Lockwood 
upon  his  crossing  of  Grinnell  Land  in  1883.22  Of  especial  inter- 
est is  his  description  of  the  ice  front  or  face  as  it  was  observed 
for  long  distances  in  the  form  of  a  perpendicular  wall  which 
he  described  under  the  name  "  Chinese  Wall."  Over  upland 
and  plain  this  wall  extended  with  little  apparent  change  in 
its  character.  At  one  place  by  pacing  and  sextant  angle  its 
height  was  estimated  at  143  feet  (see  Fig.  68). 

The  inland-ice  of  Ellesmere  Land  (see  Fig.  67)  has  been  to 


THE  ARCTIC  GLACIER  TYPE 


117 


some  extent  explored  along  its  borders  by  members  of  the 
Sverdrup  Expedition.23  The  maps  of  the  margin  in  the  vicin- 
ity of  Buchanan  Bay  display  much  the  same  characters  as 


FIG.  69.  —  Map  showing  the  supposed  area  of  inland-ice  upon  Baffin  Land  (from 
Andree's  "  Handatlas  "). 

may  be  observed  along  the  margins  of  the  better-known  ice- 
caps and  inland-ice  masses  of  the  northern  hemisphere. 

Of  the  inland-ice  of  Baffin  Land  little  is  known  (see  Fig.  69). 
There  are  some  indications  that  a  small  ice-cap  exists  upon 
the  neighboring  island  of  North  Devon. 

REFERENCES 

JWm.  Herbert  Hobbs,  "The  Cycle  of  Mountain  Glaciation,"  Geogr. 
Jour.,  vol.  36,  1910,  pp.  147,  148. 

2  W.  M.  Conway,  "An  Exploration  in  1897  of  some  of  the  Glaciers  of 
Spitzbergen,"  Geogr.  Jour.,  vol.  12,  1898,  pp.  142-147. 


118        CHARACTERISTICS  OF  EXISTING  GLACIERS 

8  It  has  not  in  most  cases  yet  been  determined  to  what  extent  the 
present  nourishment  of  these  glaciers  suffices  to  maintain  them,  or,  per 
contra,  to  what  extent  they  are  mere  waning  remnants  of  larger  pre-existing 
masses.  It  is,  however,  known  that  formerly  they  were  much  larger. 

*H.  Hess,  "Die  Gletscher,"  1904,  pp.  66,  90-92. 

5  Th.  Thoroddsen,  "Island,  Grundriss  der  Geographic  und  Geologie," 
Pet.  Mitt.  (Erganzungshefts  152,  153),  1906,  V.,  "  Die  Gletscher  Islands," 
pp.  163-208. 

6  Hans  Spethmann,  "Der  Nordrand  des  islandischen  Inlandeises  Vatna- 
jokull,"  Zeitsch.  f.  Gletscherk.,  vol.  3,  1909,  pp.  36-43. 

7  Carl  Sapper,  "Bemerkungen  iiber  einige  siidislandische  Gletscher," 
Zeitsch.  f.  Gletsch.,  vol.  3,  1909,  pp.  297-305,  two  maps  and  three  figures. 
See  especially  Fig.  3. 

8  Max  Ebeling,   "  Eine    Reise   durch  das  islandische  Siidland,"  Zeit. 
Gesellsch.  f.  Erdkunde,  Berlin,  1910,  pp.  361-382. 

9  R.  S.  Tarr,  "  Some  phenomena  of  the  glacier  margins  in  the  Yakutat 
Bay  Region,  Alaska,"  Zeit.  f.  Gletscherk.,  vol.  3,  1909,  pp.  94-96,  Fig.  6. 

10  Otto  Nordenskjold,  "Die  Polarwelt,"  1909,  pp.  42-43. 

11  F.  G.  Jackson,  "A  Thousand  Days  in  the  Arctic,"  1899,  map  5. 

12  Anthony  Fiala,  "The  Ziegler  Polar-Expedition  of  1803-05,"  1907, 
map  C. 

13  "  On  the  '  Polar  Star '  in  the  Arctic  Sea,"  vol.  1,  pp.  116-118. 

14  Professor  Hanns  Hofer,  "  Graf  Welczeks  Nordpolar-fahrt  im  Jahre 
1872,  III  Ueber  die  Gletscher  von  Nova  Zembla,"  Pet.  Mitt.,  vol.  21, 1875, 
pp.  53-56.      See  also  Commandant  Charles  Benard,  "  Dans  1'ocean  gla- 
cial et  en  Nouvelle-Zemble,"  Paris,  1910,  pp.  1-193. 

16  A.  E.  Nordenskjold,  "Gronland,"  map  on  p.  141. 

16  W.  Martin  Conway,  "An  Exploration  in  1897  of  some  of  the  Glaciers 
of  Spitzbergen,"  Geogr.  Jour.,  vol.  12,  1898,  pp.  137-158. 

17  Sir  Wm.  Martin  Conway,   "The  First  Crossing    of  Spitzbergen," 
London,  1897,  pp.  371,  2  maps. 

18  O.  Nordenskjold,  I.e.,  p.  52. 

19  See  O.  Nordenskjold,  Die  Polarwelt,  p.  52. 

20 A.  E.  Nordenskjold,  "Die  Schlittenfahrt  der  schwedischen  Expedi- 
tion im  nordostlichen  Theile  von  Spitzbergen,  24  April-15  Juni  1873,"  Pet. 
Mitt.,  vol.  19,  1873,  pp.  450-453. 

21  Nordenskjold,  I.e.,  pp.  255-257. 

22  A.  W.  Greely,  "Report  on  the  Proceedings  of  the  United  States  Ex- 
pedition to  Lady  Franklin  Bay,  Grinnell  Land,"  vol.  1,  especially  Ap- 
pendix No.  86,  pp.  274-279,  pis.  1-4.      See  also  Salisbury,  Jour.  Geol., 
vol.  3,  p.  890. 

23  Otto  Sverdrup,  "New  Land,"  2  vols.,  London,  1904,  pp.  496-504. 


CHAPTER  VIII 

PHYSIOGRAPHY  OF  THE  CONTINENTAL  GLACIER  OF 
GREENLAND 

General  Form  and  Outlines. — The  Inland-ice  of  Greenland, 
we  have  now  good  reason  to  believe,  has  the  form  of  a  flat 
dome,  the  highest  surfaces  of  which  lie  somewhat  to  the 
eastward  of  the  medial  line  of  the  continent.1  This  ice  dome 
envelops  all  but  a  relatively  narrow  marginal  rim.  The  mar- 
ginal ribbon  of  land  is  usually  from  five  to  twenty-five  miles 
in  width,  may  decrease  to  nothing,  but  in  two  nearly  opposite 
stretches  of  shore  it  widens  to  from  sixty  to  one  hundred 
miles  (see  Fig.  70). 

At  the  heads  of  many  deep  fjords  long  and  narrow  mar- 
ginal tongues  pushing  out  from  the  central  mass  reach  to  be- 
low sea  level ;  and  within  three  limited  stretches  of  shore  the 
ice  mantle  overlaps  the  borders  of  the  continent  and  reaches 
the  sea  in  a  broad  front.  The  longest  of  these  begins  near 
the  Devil's  Thumb  on  the  west  coast  at  about  latitude  74' 30", 
and  extends  with  some  interruptions  for  about  one  hundred 
and  fifty  miles  along  the  coast  of  Melville  Bay.2  Where 
crossed  by  Nansen  near  the  parallel  of  64°,  and  hence  near 
the  southern  margin,  and  also  where  traversed  by  Peary 
near  its  northwestern  borders,  the  inland-ice  has  revealed 
much  the  same  features.  The  great  central  area  has  never 
been  entered,  although  Baron  Nordenskjold  and  Commander 

119 


120        CHARACTERISTICS  OF  EXISTING  GLACIERS 

Peary  have  each  passed  somewhat  within  the  margin  near 
the  latitude  of   68°,  and  Jensen  near  latitude  63° 3  (see 
Fig.  70). 
In  1893  Garde  at  the  extreme  southern  end  of  the  con- 


FIG.  70.  —  Map  of  Greenland,  showing  the  outlines  of  the  inland-ice  (from 
Andree's  "Handatlas,"  but  corrected  for  the  northeast  shore  from  data  of  the 
Danish  expedition  of  1908).  The  routes  of  the  various  expeditions  on  the 
inland-ice  have  also  been  added. 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       121 


46  30 


tinent  (latitude  61°-62°)  penetrated  the  area  of  the  inland- 
ice  a  distance  of  about  sixty-five  miles.4  The  route  of 
the  expedition  and  the 
contours  of  the  surface 
are  given  in  Fig.  71. 5 
The  first  partially  suc- 
cessful attack  upon 
the  inland-ice  was  that 
of  Dr.  I.  I.  Hayes, 
Commander  of  the 
United  States  Explor- 
ing Expedition,  which 
spent  the  winter  of 
1860-1861  on  Smith 
Sound  in  northwestern 
Greenland.  Hayes  ^ 
succeeded  in 
reaching  a  point 
seventy  miles 
within  the  margin 
of  the  ice  at  an 

plpvatirm  nf  ahrmt     FIG.  71.  — Route  of  Garde  across  the  margin  of  the  inland- 

elevation  01  about          ice  o£  gouth  Greenland  in  1893  (after  Garde) 
5000  feet.6 

Recently  (1907)  Mylius  Ericksen  met  his  tragic  death  in 
crossing  the  inland-ice  in  northeast  Greenland,  but  his  re- 
sults, most  fortunately  recovered,  through  the  heroism  of 
Bronlund,  are  not  yet  published.  Yet  such  is  the  monotony 
of  the  surface  thus  far  revealed,  and  such  the  uniformity  of 
conditions  encountered,  that  there  is  little  reason  to  think 
future  explorations  in  the  interior  will  disclose  anything  but 
a  desert  of  snow,  with  such  small  variations  from  a  horizon- 
tal surface  as  are  not  strikingly  apparent  to  the  traveller  at 
any  one  observing  point. 

Nansen  has  laid  stress  upon  the  close  adherence  of  the 


122         CHARACTERISTICS  OF  EXISTING  GLACIERS 

curve  of  his  section  to  that  of  a  circle,  and  has  attempted  to 
apply  this  interpretation  to  the  sections  of  both  Norden- 
skjold  and  Peary  made  near  the  latitude  of  Disco  Bay.7  If 
the  marginal  portions  of  the  sections  be  disregarded,  this  in- 
terpretation is  possible  for  Nansen's  own  profile,  since  it  is 


FIG.  72. —  Sketch  of  the  east  coast  of  Greenland  near   Cape  Dan.       Shows  the 
inland-ice  and  the  work  of  marginal  mountain  glaciers   (after  Nansen). 

in  any  case  very  flat;  but  inasmuch  as  the  margins  only 
were  traversed  in  the  other  sections,  the  conclusions  drawn 
from  them  are  likely  to  be  misleading  when  extended  into 
the  unknown  interior. 

Hess,8  correcting  Nansen's  data  so  as  to  take  account  of  the 
curvature  of  the  earth,  finds  the  radius  of  this  circle  of  the 
section  to  be  approximately  3700  km.  (instead  of  10,380  km., 
as  given  by  Nansen).  This  radial  distance  being  consider- 
ably less  than  the  average  for  the  earth's  surface,  the  curva- 
ture of  the  ice  surface  where  crossed  by  Nansen  is  consider- 
ably more  convex  than  an  average  continental  section. 


FIG.  73.  —  The  section  across  the  inland-ice  of  Greenland,  near  the  64th  parallel  of 
latitude  in  natural  proportions  and  with  vertical  scale  ten  times  the  horizontal 
(after  Nansen). 

We  are  absolutely  without  knowledge  concerning  either  the 
thickness  of  the  ice  shield  or  the  elevation  of  the  rock  base- 
ment beneath  it,  though  a  height  of  the  snow  surface  of  ap- 
proximately 9000  feet  was  reached  by  Nansen  at  a  point 
where  it  could  hardly  be  expected  to  be  a  maximum.  The 
snow  surface  to  the  north  of  his  section  was  everywhere  ris- 


THE   CONTINENTAL  GLACIER  OF  GREENLAND       123 

ing,  and  it  is  likely  that  it  attains  an  altitude  to  the  north- 
eastward well  above  10,000  feet. 

Though  doubtless  almost  flat  within  its  central  portions, 
and  only  gently  sloping  outward  at  distances  of  from  sev- 
enty-five to  one  hundred  miles  within  its  margin,  the  snow 
surface  falls  away  so  abruptly  where  it  approaches  its  bor- 
ders as  to  be  often  quite  difficult  of  ascent  (see  Fig.  73). 9  The 
monotony  of  the  flatly  arched  central  portion  of  the  isblink10 


C. 


FIG.  74. —  Comparison  of  the  several  profiles  across  the  margin  of  the  inland-ice: 
(a)  at  latitude  69|°  on  the  west  coast  (Peary) ;  (6)  at  latitude  68£°  on  the  west 
coast  (Nordenskjold) ;  (c)  at  latitude  64°  on  the  west  coast  (Nansen) ;  and  (d)  at 
latitude  64|°  on  the  east  coast  (Nansen). 

gives  place  to  wholly  different  characters  as  the  margins  are 
approached.  The  ice  descends  in  broad  terraces  or  steps, 
which  have  treads  of  gentle  inclination  but  whose  risers  are 
of  greater  steepness,  and  this  steepness  is  rapidly  accelerated 
as  the  margin  is  neared.  In  Fig.  74  have  been  placed  to- 
gether for  comparison  the  profiles  of  Peary,  Nordenskjold, 


124         CHARACTERISTICS  OF  EXISTING  GLACIERS 

and  Nansen  tin  the  different  routes  which  they  travelled 
toward  the  interior  from  the  coast. 

The  margins  of  the  Greenland  continent  where  uncovered 
by  the  ice,  are  generally  mountainous,  with  heights  reaching 
in  many  cases  to  between  5000  and  8000  feet  on  the  east 
shore  n  and  between  5000  and  6000  feet  on  the  west  shore. 
The  bordering  ice-caps  within  these  areas  are  developed  in 
special  perfection  on  the  islands  of  the  archipelago  about 
King  Oscars  fjord  and  Kaiser  Franz  Josef  fjord  on  the  east 
coast  near  latitude  75°  N.,  as  these  have  been  mapped  by  the 
Swedish  Greenland  Expedition  of  1899  (see  Fig.  75). 12  The 


FIG.  75.  —  Map  of  the  region  about  King  Oscars  and  Kaiser  Franz  Josef  fjords, 
Eastern  Greenland,  showing  the  areas  of  the  numerous  ice-caps  (after  P.  Dusen). 

work  of  mountain  glaciers  about  King  Oscars  fjord  is  clearly 
displayed  by  Nathorst's  photograph  reproduced  in  plate  22 
A.  Essentially  the  same  features  are  shown  also  to  the  right 
in  Fig.  72  (p.  122). 


PLATE  22. 


A.  Fretted  upland  carved  by  mountain  glaciers  about  King  Oscar's  Fjord,  eastern 
Greenland.  The  highest  points  are  from  1360  to  1570  metres  above  the  sea 
(after  Nathorst). 


B.  Front  of  the  Bryant  glacier  tongue  showing  the  vertical  wall  and  stratification 
of  ice.  It  also  shows  the  absence  of  rock  debris  from  the  upper  layers  (after 
Chamberlin). 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       125 


While  we  are  without  absolute  knowledge  of  the  relief  of 
the  land  beneath  most  of  the  inland-ice,  we  know  that  the 
mountainous  upland  of  the 
coast  extends  well  within 
the  ice  margins,  since  the 
peaks  project  through  the 
surface  as  ice-bounded  rock 
islands  or  nunataks.  The 
irregularities  of  this  base- 
ment and  the  submergence 
and  consequent  drowning 
of  the  valleys  to  form  deep 
fjords  within  the  marginal 
zones,  largely  account  for 
the  markedly  lobate  out- 
lines of  the  so-called  isblink 
or  inland-ice,  as  well  as  for 
the  ice-caps  and  mountain 
glaciers,  which,  originating 
in  the  outlying  plateaus 
and  mountains,  form  a 
fringe  about  the  central  ice 
mass. 

It  has  been  shown  to  be 
characteristic  of  the  ice- 
caps and  smaller  inland-ice 
areas  of  the  Arctic  region 
outside  of  Greenland,  that 
their  lobate  margins  are  in 
part  accounted  for  by  ex- 
tensions Of  the  Cap  Upon  FIG.  76.  —  Map  of  a  glacier  tongue,  which 

the  plateau  between  inter-       "^  **°™  *h,e  inland-ice  down  the 

f  Umanak  fjord  (after  von  Drygalski). 

sectmg  valleys  or  fjords,  as 

well  as  by  extensions  down  these  valleys.     These  latter 


126        CHARACTERISTICS  OF  EXISTING  GLACIERS 

extensions  of  the  ice-sheets  are,  however,  much  the  nar- 
rower. Identically  the  same  features  are  found  to  char- 
acterize the  Greenland  inland-ice  as  well.  The  manner  in 
which  this  occurs  in  Greenland  has  been  well  brought  out 
in  a  map  and  section  by  Helland  13  of  the  Kangerdlugsuak 
fjord  and  glacier,  but  even  better  by  recent  maps  of  the 
Petermann  fjord  by  Peary  (Fig.  81,  p.  133)  and  the  Umanak 
fjord  by  von  Drygalski14  (see  Fig.  76).  The  manner  in  which 
the  ice  sometimes  descends  from  the  higher  levels  over  the 
steep  walls  of  the  fjords  has  been  strikingly  brought  out  in  a 
photograph  of  the  Foetal  glacier  (see  Fig.  77). 15 


FIG.   77. —  Tongues  of  ice  descending  from  the  Fostal  glacier,  McCormick  Bay 

(after  Peary) . 

As  already  stated,  within  one  limited  stretch  upon  the 
west  coast  the  ice  mantle  overlaps  the  borders  of  the  con- 
tinent and  reaches  the  sea  in  a  broad  front.  This  stretch 
of  coast  begins  near  the  Devil's  Thumb  at  about  latitude 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       127 


North  East 
and. 


74°  30'  and  extends,  with  some  interruption,  for  about  150 
miles  along  the  coast  of  Melville  bay.16  On  the  northeast 
coast  the  recent  explorations  of  the  Danes  indicate  that 
there  are  two 
stretches  of  20 
and  60  miles, 
respectively, 
within  which 
the  ice  in  like 
manner  reaches 
the  sea.  These 
occur  on  Jokull  bay 
and  on  the  north 
shore  of  the  North  East 
Foreland  (see  Fig.  78). 17 
The  Ice  Face  or  Front. 
—  Concerning  the  form 
of  the  front  of  the  inland- 
ice  where  it  lies  upon  the 
land,  widely  different 
descriptions  have 
been  furnished  from 
different  districts. 
It  is  necessary  to 
remember  that  the 
continent  of  Green- 
land stretches  northward  through  nearly  24°  of  latitude,  and 
after  due  regard  is  had  to  this  consideration,  the  differences 
in  configuration  may,  perhaps,  be  found  to  be  but  expres- 
sions of  climatic  variation.  Those  who  have  studied  the 
land  margin  of  the  isblink  in  North  Greenland,  all  call 
attention  to  the  precipitous  and  generally  vertical  wall 
which  forms  the  ice  face  (see  plate  22  B).  As  a  result  of 
shearing  and  overthrusting  movements  within  the  ice  near 


FIG.  78.  —  Map  of  the  Greenland  shore  in  the 
vicinity  of  the  North  East  Foreland  (after 
Trolle). 


128        CHARACTERISTICS  OF  EXISTING  GLACIERS 

its  margin,  as  well  as  to  the  effect  of  greater  melting  about 
the  rock  fragments  imbedded  in  the  lower  layers  of  the  ice, 
the  face  sometimes  even  overhangs  in  a  massive  ice  cornice 
at  the  summit  of  the  wall  (see  plate  23  A).18 

That  to  this  remarkable  steepness  of  the  ice  face  as  ob- 
served north  of  Cape  York  there  are  exceptions,  has  been 
mentioned  by  both  Chamberlin  and  Salisbury,  but  Peary 
has  also  emphasized  the  vertical  face  as  a  widely  character- 
istic feature  of  North  Greenland.  The  recent  Danish  Expe- 
dition to  the  northeast  coast  of  Greenland  has  likewise  fur- 
nished examples  of  such  vertical  walls.  An  instance  where 
the  ice  face  appears  as  a  beautifully  jointed  surface  some- 
what resembling  the  rectangular  joint  walls  in  the  quarry 
faces  of  certain  compact  limestones,  is  reproduced  from  the 
report  of  the  expedition  in  plate  23  B.19 

Attention  has  already  been  called  to  the  precipitous  front, 
the  so-called  "  Chinese  Wall,"  which  Lieutenant  Lockwood 
found  to  form  the  land  face  of  the  inland-ice  of  Ellesmere 
Land  —  a  face  which  was  followed  up  and  down  over  irregu- 
larities of  the  land  surface,  and  whose  height  in 'one  place 
was  roughly  measured  as  143  feet  (see  Fig.  68,  p.  116). 

From  central  and  southern  Greenland,  on  the  other  hand, 
we  hear  little  of  such  ice  cliffs  as  have  been  described,  and 
Tarr  in  studies  about  the  margin  of  the  Cornell  extension  of 
the  isblink20  has  shown  that  here  the  vertical  face  is  the  ex- 
ception.21 The  normal  sloping  face  as  there  seen  is  repre- 
sented in  plate  24  A.  In  following  the  ice  face  for  fifteen 
miles,  its  slopes  were  here  found  to  be  sufficiently  moderate 
to  permit  of  frequent  and  easy  ascent  and  descent.  Inas- 
much as  these  sloping  forms  are  characteristic  of  the  ice 
front  in  the  warmer  zones,  and  further  correspond  to  that 
generally  characteristic  of  mountain  glaciers  in  lower  lati- 
tudes, it  seems  likely  that  its  occurrence  in  Greenland  is 
limited  to  districts  where  surface  ablation  plays  a  larger  role. 


PLATE  23. 


Portion  of  the  southeast  face  of  the  Tuktoo  glacier  tongue  showing  the 
projection  of  the  upper  layers  apparently  as  a  result  of  overthrust  (after 
Chamberlin). 


B.    Ice-face  at  eastern  margin  of  the  inland-ice  of  Greenland  in  latitude  77°  30'  N. 

(after  Trolle). 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       129 

In  Northeast  Greenland  (lat.  77°-82°),  according  to  the 
Danes,  "  the  frontier  of  the  inland-ice  is  in  some  places 
quite  steep,  in  other  places  you  might  have  mounted  the 
inland-ice  without  knowing  it." 

Features  within  the  Marginal  Zone.  --The  larger  terraces 
upon  the  ice-slope,  Nansen  has  ascribed  to  peculiarities  of 
the  rock  floor  on  which  the  ice  rests.  Where  the  slopes 
become  still  more  accelerated  toward  the  margin  of  the  ice, 
deep  crevasses  appear  upon  these  steps  running  parallel  to 
their  extension,  and  hence  parallel  to  the  margins  of  the  ice. 
Nansen  found,  however,  that  such  crevasses  were  restricted 
to  the  outer  seven  or  eight  miles  on  the  eastern  side  of  his 
section,  and  to  the  outer  twenty-five  miles  on  its  western 
margin.  Peary  in  his  reconnoissance  across  the  ice  border 


FIG.  79.  —  A  series  of  parallel  crevasses  on  the  inland-ice  of  South 
Greenland  (after  Garde). 

in  latitude  69^-°,  saw  such  crevasses  while  they  were  open- 
ing and 'the  surface  snow  was  sinking  into  the  cleft  thus 
formed.  The  visible  opening  of  the  cleft  was  accompanied 
by  peculiar  muffled  reports  which  rumbled  away  beneath 
the  crust  in  every  direction.22 

In  addition  to  the  crevasses  which  develop  transversely 


130         CHARACTERISTICS  OF  EXISTING  GLACIERS 


to  the  main  direction  of  ice  movement,  and  which  are  with 
much  probability  located  over  "  steps  "  in  the  rock  floor, 
there  are  evidently  others  which  fall  in  a  somewhat  different 
category.  The  series  of  parallel  crevasses  resembling 
ravines  which  are  figured  by  Garde  23  and  take  their  course 
over  the  gently  swelling  surface  of  the  ice  (see  Fig.  79) 
bear  more  resemblance  to  the  longitudinal  crevasses  which 
one  finds  between  the  nunataks  upon  the  surface  of  the 
plateau  glaciers  of  Norway,  as,  for  example,  the  Hardanger- 
jokull.  Of  very  considerable  interest  also  are  the  rec- 
tangular networks  of  crevasses  which  are  described  by  the 
same  author  from  near  the  margin  of  the  ice  (see  Fig.  80)  ,24 


FIG.  80.  —  Rectangular  network  of  crevasses  on  the  surface  of  the  inland- 
ice  near  its  margin  in  South  Greenland  (after  Garde). 

This  network  recalls  the  rectangular  system  of  crevasses 
which  was  observed  by  the  German  Expedition  on  the  in- 
land-ice of  Kaiser  Wilhelm  Land  (see  Fig.  129). 

Of  the  terraced  slope  and  its  fading  into  the  plateau  above 
Peary  says :  — 

The  surface  of  the  "  ice-blink  "  near  the  margin  is  a  succession  of 
rounded  hummocks,  steepest  and  highest  on  their  landward  sides, 
which  are  sometimes  precipitous.  Farther  in  these  hummocks 


PLATE  24. 


A.    Normal  slope  of  the  inland-ice  at  the  land  margin  near  the  Cornell  tongue 

(after  Tarr). 


B.    Hummocky  moraine  on  the  margin  of  the  Cornell  glacier  tongue  (after  Tarr). 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       131 

merge  into  long,  flat  swells,  which  in  turn  decrease  in  height  towards 
the  interior,  until  at  last  a  flat  gently  rising  plain  is  revealed  which 
doubtless  becomes  ultimately  level.25 

In  sketching  the  general  form  of  the  Greenland  conti- 
nental glacier,  it  has  been  stated  that  the  highest  portion  of 
the  shield  lies  to  the  eastward  of  the  medial  line  of  the  con- 
tinent. This  is  shown  by  Nansen's  section,  and  is  empha- 
sized by  Peary,  who  says :  - 

That  the  crest  of  the  Greenland  continental  ice  divide  is  east  of 
the  country's  median  line  there  can  be  no  doubt.26 

By  von  Drygalski 27  this  lack  of  symmetry  of  the  ice 
mass  has  been  ascribed  to  excessive  nourishment  upon  the 
east,  whereas  the  losses  from  melting  and  from  the  discharge 
of  bergs  occur  mainly  upon  the  west.  The  mountains  of 
the  east  are,  he  states,  completely  surrounded  by  ice  so  that 
peaks  alone  project,  while  the  mountains  of  the  west  stand 
isolated  from  the  ice.  In  attempting  to  make  the  eccentric 
position  of  the  boss  in  the  ice  shield  depend  upon  the  con- 
figuration of  the  underlying  rock  surface,  von  Drygalski 
has  been  less  convincing,  for  we  know  that  the  Scandinavian 
continental  glacier  of  Pleistocene  times  moved  northwest- 
ward from  the  highest  surface  of  the  ice-shield  up  the  grade 
of  the  rock  floor,  and  pushed  out  through  portals  in  the  moun- 
tain barrier  which  lies  along  the  common  boundary  of 
Sweden  and  Norway. 

We  shall  see,  moreover,  that  the  nourishment  of  the 
Greenland  ice  is  by  a  different  process  than  that  which  he 
has  assumed.  Still  there  would  appear  to  be  a  clear  parallel 
between  the  marginal  terraces  of  the  inland-ice  with  their 
crevassed  steep  surfaces,  and  the  plateaus  and  ice-falls  which 
alternate  upon  the  slopes  of  every  mountain  glacier  which 
descends  rapidly  in  its  valley. 


132        CHARACTERISTICS  OF  EXISTING  GLACIERS 

Superimposed  upon  the  flats  of  the  larger  ice  terracesr 
there  are  undulations  of  a  secondary  order  of  magnitude, 
and  these  Nansen  ascribed  to  the  drifting  of  snow  by  the 
wind.  To  the  important  action  of  wind  in  moulding  the 
surface  of  the  inland-ice  we  shall  refer  again.  There  are  in 
addition  many  other  irregularities  of  the  surface  due  to 
differential  melting,  and  while  of  very  great  interest,  their 
consideration  may  profitably  be  deferred  until  the  meteoro- 
logical conditions  of  the  region  have  been  discussed.  There 
are,  however,  other  features  which  like  the  broader  terraces 
are  clearly  independent  of  meteorological  conditions,  and 
which  are,  therefore,  best  considered  in  this  connection. 

Dimples  or  Basins  of  Exudation  above  the  Marginal 
Tongues.  —  Seen  from  the  sea  in  Melville  bay  on  the  north- 
west coast,  the  inland-ice  offers  special  advantages  for  observ- 
ing its  contours  in  sections  parallel  to  its  front,  that  is  to  sayr 
in  front  elevation.  Here  only  upon  the  west  coast  the  ice 
extends  beyond  the  borders  of  the  land  and  is  cut  back  by 
the  sea  to  form  cliffs.  These  ice  cliffs  are  interrupted  by 
rocky  promontories  which  are  surrounded  on  all  sides  but 
the  front  by  ice,  and  hence  in  reality  the  cliff  furnishes  us 
with  sections  through  nunataks  and  inland-ice  alike.  Says- 
Chamberlin : 28  — 

Only  a  few  of  the  promontories  of  the  coast  rise  high  enough  to 
be  projected  across  this  sky-line  and  interrupt  the  otherwise  con- 
tinuous stretch  of  the  glacial  horizon.  The  ice  does  not  meet  the 
sky  in  a  simple  straight  line.  It  undulates  gently,  indicating  some 
notable  departure  of  the  upper  surface  of  the  ice  tract  from  a  plane. 
As  the  ice-field  slopes  down  from  the  interior  to  the  border  of  the 
bay,  it  takes  on  a  still  more  pronounced  undulatory  surface.  It  is 
not  unlike  some  of  our  gracefully  rolling  prairies  as  they  descend 
from  uplands  to  valleys,  when  near  their  middle-life  development. 

The  two  1200-mile  sledge  journeys  of  Peary  in  the  years- 
1891-1892  and  1893-1895  across  the  northern  margin  of  the- 


THE   CONTINENTAL  GLACIER  OF  GREENLAND       133 


"  Great  Ice  "  of  Green- 
land, have  added  much 
to  our  knowledge  of  the 
physiography  of  the 
inland-ice.  These  jour- 
neys were  made  on 
nearly  parallel  lines  at 
different  distances  from 
the  ice  border,  and  so; 
if  studied  in  relation  to 
each  other,  they  display 
to  advantage  the  con- 
figuration of  the  ice 
surface  near  its  margin 
(see  Fig.  81).  The 
routes  were  for  the  most 
part  nearly  straight  and 
ran  at  nearly  uniform 
elevations  which  ranged 
from  5000  to  8000  feet 
above  the  sea.29  In  the 
sections  nearest  the 
coast,  however,  the 
route  at  first  ascended 
a  gentle  rise  to  a  flatly 
domed  crest  upon  the 
ice,  only  to  descend  sub- 
sequently into  a  broad 
swale  of  the  surface,  the 
bottom  of  which  might 
be  described  as  a  plain, 
and  which  was  con- 
tinued in  the  direc- 
tion of  the  coast  by  a 
tongue-like  extension  of 


FIG.  81.  —  Map  showing  routes  of  sledge  jour- 
neys in  North  Greenland  in  their  relation  to 
the  margin  of  the  ice  (after  Peary). 


134        CHARACTERISTICS  OF  EXISTING  GLACIERS 

the  ice,  such  as  the  tongue  in  Petermann  fjord  between  Hall 
Land  and  Washington  Land  (Fig.  81).  On  the  farther  side 
of  this  basin-like  depression,  the  surface  again  rose  until 
another  domed  crest  had  been  reached,  after  which  a 
descent  began  into  a  swale  similar  to  the  first.  On  the 
return  journey  by  keeping  farther  from  the  ice  margin  these 
elongated  dimples  upon  the  ice  surface  were  avoided.  The 
broad  domed  surfaces  which  separate  the  dimples  clearly  lie 
over  the  land  ridges  between  the  valleys  down  which  the 
glacier  tongues  descend  toward  the  sea. 

Peary  has  referred  to  these  dimples  on  the  surface  of  the 
inland-ice  as  "  basins  of  exudation/'  and  has  compared  the 
cross  profile  in  its  ups  and  downs  to  that  of  a  railroad  located 
along  the  foot-hills  of  a  mountain  system.30  In  his  earlier 
reconnaissance  of  the  isblink  from  near  Disco  Bay,  Peary 
describes  such  a  dimple  above  the  Jakobshavn  ice  tongue 
"  stretching  eastward  into  the  '  ice-blink/  like  a  great  bay," 
as  a  feeder  basin.31  The  exact  form  of  such  dimples  upon  the 
ice  surface  is  well  brought  out  in  von  Drygalski's  map 
of  the  Asakak  glacier  tongue  on  the  Umanak  fjord  (see 
Fig.  76,  p.  125).32 

We  may  easily  account  for  the  existence  of  these  dimples 
by  drawing  a  parallel  from  the  behavior  of  water  as  it  is 
being  discharged  from  a  lake  through  a  narrow  and  steeply 
inclined  channel.  Under  these  circumstances  the  surface 
is  depressed  through  the  indrawing  of  the  water  on  all  sides 
to  supply  the  demands  of  the  outflowing  current.  That 
within  the  upper  portions  of  the  glacier  tongues  of  the  Green- 
land isblink  the  ice  flows  with  a  quite  extraordinary  velocity 
has  long  been  known.  Values  as  high  as  100  feet  per  day 
have  been  determined  upon  the  Upernavik  glacier.33  By 
more  accurate  methods,  von  Drygalski  has  obtained  on  one 
of  the  ice  tongues  which  descends  to  a  fjord  a  rate  of  about 
18  meters  or  59  feet  in  twenty-four  hours.34  Upon  the  in- 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       135 

land-ice  some  distance  back  from  the  head  of  the  fjord,  on 
the  other  hand,  a  rate  was  measured  of  only  one  to  two 
centimeters  per  day. 

Scape  Colks  and  Surface  Moraines.  —  The  velocities  of 
ice  movement  which  obtain  within  and  about  the  heads 
of  the  glacial  outlets  are,  there  is  thus  every  reason  to  be- 
lieve, as  different  as  possible  from  the  ordinary  general  out- 
ward movement  of  the  inland-ice.  Within  this  marginal 
zone  areas  of  exceptional  velocity  of  the  inland-ice  are  likely 
to  be  found  wherever  its  progress  is  interfered  with  by  the 
projecting  nunataks.  Just  as  jetties  by  constricting  the 
channels  greatly  accelerate  the  velocity  of  stream  flow 
within  those  channels,  so  here  within  the  space  between 
neighboring  nunataks  a  local  high  rate  of  flow  in  the  ice  is 
developed.  An  inevitable  and  quite  important  consequence 
of  this  constriction  was  long  ago  pointed  out  by  Suess  and 
illustrated  by  the  area  between  Dalager's  nunataks  near  the 
southwestern  border  of  the  isblink.35  Here  again  the  conduct 
of  water  which  is  being  discharged  through  narrow  outlets 
has  supplied  both  the  illustration  and  the  explanation.  In 
the  regulation  of  the  flow  of  the  Danube  below  Vienna,  the 
river  was  partially  closed  by  a  dam,  the  Neu-Haufen  dike, 
and  the  floor  in  the  channel  below  the  dike  was  paved  with 
heavy  stone  blocks.  The  effect  of  thus  narrowing  the  chan- 
nel of  the  river  was  to  raise  the  level  of  the  water  above  the 
dike  by  almost  a  metre,  and  under  this  increased  head 
the  current  tore  out  the  heavy  stone  paving  of  the  floor  of 
the  channel  and  dug  a  depression  above  as  well  as  below 
the  outlet.  This  excavation  by  the  current  represented  a 
hole  dug  to  a  depth  of  about  fifteen  metres.  The  blocks 
which  had  been  torn  out  from  the  pavement  were  left  in  a 
crescent-shaped  border  to  the  depression  upon  its  down- 
stream side  (see  Fig.  82  a). 

The  position  of  a  surface  moraine  which  stretches  in  a 


136        CHARACTERISTICS  OF  EXISTING   GLACIERS 


sweeping  arc  from  the  lower  edge  of  one  of  Dalager's  nuna- 
taks  to  a  similar  point  upon  its  neighbor,  indicates  a  com- 
plete parallel  between  the  motion  of  the  ice  and  the  water 
at  the  Neu-Haufen  dyke,  the  rock  debris  of  the  deeper  ice 


FIG.  82.  —  a,  Closure  of  the  Neu-Haufen  dyke,  Schilttau  in  the  regulation  of  the 
Danube  below  Vienna  (after  Taussig)  ;  b,  Scape  colks  near  Dalager's  Nunataks 
(after  Jensen  and  Kornerup). 

layers  being  here  brought  up  to  the  surface.  Study  of  the 
Scandinavian  inland-ice  of  late  Pleistocene  times  throws 
additional  light  upon  the  nature  of  this  process.  Flowing 
from  a  central  boss  near  the  head  of  the  Gulf  of  Bothnia, 
the  ice  pushed  westward  and  escaped  through  narrow  portals 
in  the  escarpment  which  now  follows  the  international  boun- 
dary of  Sweden  and  Norway.  This  constriction  of  its  current 
has  been  appealed  to  by  Suess  to  account  for  the  interesting 
glint  lakes  which  to-day  lie  across  this  barrier  and  extend 
both  above  and  below  the  former  outlets  for  the  ice.36  Lakes 
which  have  this  origin  he  has  described  under  the  term  "  scape 
colks."  Perhaps  if  examined  more  carefully,  we  should  find 
that  the  bringing  up  of  the  englacial  debris  to  the  surface 
of  the  ice,  is  only  partially  due  to  the  inertia  of  motion  in  the 
ice.  With  the  more  rapid  flow  of  the  ice  within  the  con- 
stricted portion,  the  basic  layers,  shod  as  they  are  with 
rock  fragments,  accomplish  excessive  abrasion  upon  the  rock 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       137 

bed.  This  is  in  accord  with  Penck's  law  of  adjusted  cross- 
sections  in  glacial  erosion.  Where  the  ice  channel  broadens 
below  the  nunataks,  the  abrasion  again  becomes  normal  so 
that  a  wall  develops  at  this  place  in  the  course  of  the  stream. 

Here,  therefore,  a  new  process  comes  into  play  due  to  the 
peculiar  properties  of  the  plastic  ice,  a  process  which  has  been 
illustrated  in  the  formation  of  drumlins  beneath  former 
continental  glaciers,  and  has  been  given  an  experimental 
verification.  Case  has  shown  that  paraffin  mixed  with 
proper  proportions  of  refined  petroleum,  and  maintained  at 
suitable  temperatures,  can  be  forced  by  means  of  plungers37 
through  narrow  boxes  open  at  both  ends.  It  was  shown 
in  the  experiments  that  an  obstruction  interposed  at  the 
bottom  and  in  the  path  of  the  moving  paraffin,  forced  the 
bottom  layers  upward,  and  this  upward  movement  continued 
beyond  the  position  of  the  obstruction.  The  experiments 
of  Hess38  give  results  which  are  consistent  with  those  of  Case. 
Hess  employed  in  his  experiments  parallel  wax  disks  of  alter- 
nating red  and  white  colors,  and  these  were  forced  under 
hydraulic  pressure  through  a  small  opening.  It  was  found 
that  the  layers  turn  up  to  the  surface  in  this  "  model  glacier  " 
apparently  as  a  result  of  the  friction  upon  the  bottom,  and 
at  only  moderate  distances  from  the  opening  where  the 
energy  of  the  active  moving  substance  pressing  from  the  rear 
has  to  some  extent  been  dissipated. 

In  Chamberlin's  studies  of  certain  Greenland  glaciers,  he 
was  permitted  to  observe  the  effect  upon  the  motion  of  the 
glacier  of  a  low  prominence  in  its  bed.  These  observations 
are  confirmatory  of  the  experiments  described.39 

The  swirl  colks  or  eddies  which  Suess  has  suggested  as 
occurring  below  nunataks,  in  order  to  account  for  certain 
lakes  in  Norway,  seem  to  be  much  less  clear,  and  it  is  a 
little  difficult  to  assume  an  eddy  in  the  ice  which  is  in  any 
way  comparable  to  the  eddies  of  water. 


138        CHARACTERISTICS  OF  EXISTING  GLACIERS 

Marginal  Moraines.  —  Inasmuch  as  the  rock  appears  above 
the  surface  of  the  ice  of  the  Greenland  continental  glacier 
only  in  the  vicinity  of  its  margins,  and  here  only  as  small 
islands  or  nunataks,  the  rock  debris  carried  by  the  Green- 
land ice  must  be  derived  almost  solely  from  its  basement. 
As  described  in  detail  by  Chamberlin,  it  is  the  lower  100 
feet  of  ice  to  which  englacial  debris  is  largely  restricted.40 
Medial  moraines,  if  the  term  may  be  properly  applied  to 
those  ridges  of  rock  debris  which  upon  the  surface  of  the  ice 
go  out  from  the.  lower  angles  of  nunataks,  have  been  fre- 
quently described  by  Nansen  and  others.  They  seem  to 
differ  but  little  from  certain  of  the  medial  moraines  which 
have  been  described  in  connection  with  the  larger  mountain 
glaciers. 

Nansen  has  mentioned  heavy  terminal  moraines  in  the 
Austmann  Valley,  where  he  came  down  from  the  inland-ice 
after  crossing  the  continent.  The  material  of  these  moraines 
consisted  mainly  of  rounded  and  polished  rock  fragments, 
and  is  obviously  englacial  material.41  Along  the  land  margin 
of  the  Cornell  ice  tongue  Tarr  found  a  nearly  continuous 
morainic  ridge  parallel  to  the  ice  front.  This  ridge  usually 
rests  at  the  base  of  the  ice  foot,  and  is  sometimes  a  part  of 
this  foot,  wherever  debris  has  accumulated  and  protected 
the  ice  beneath  from  the  warmth  of  the  sun.  Such  an  accu- 
mulation causes  this  part  of  the  glacier  to  rise  as  a  ridge. 
In  other  cases  the  ridge  is,  however,  separated  from  the  ice 
margin,  and  sometimes  there  are  several  parallel  ridges  from 
which  the  ice  front  has  successively  withdrawn 42  (see  plate 
24  B). 

According  to  von  Drygalski  the  marginal  moraines  of  the 
Greenland  ice  sheet,  as  regards  their  occurrence,  form,  and 
composition,  are  in  every  way  like  those  remaining  in 
Northern  Europe  from  the  time  of  the  Pleistocene  glaciation, 
and  this  is  true  of  those  which  run  along  the  present  border 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       139 

of  the  inland-ice  as  well  as  of  those  still  mightier  ancient 
moraines  which  follow  at  certain  distances.43  These  moraines 
are  generally  closely  packed  blocks  with  relatively  slight 
admixture  of  finer  material.  They  are  the  largest  where  the 


FIG.  83.  —  Diagram  to  show  the  effect  of  a  basal  obstruction  in  the  path  of  the  ice 
near  its  margin  (after  Chamberlin). 

ice  border  enters  the  plains,  or  pushes  out  upon  a  gentle 
slope,  and  they  are  smallest  where  the  ice  passes  steep  rocky 
angles. 

It  is  worthy  of  note  that  the  marginal  moraines  of  Green- 
land become  locally  so  compact  and  resistant  that  they 


FIG.  84.  —  Surface  marginal  moraine  of  the  inland-ice  of  Greenland  (after 

Chamberlin). 

oppose  a  firm  obstruction  to  the  ice  movement.  Then  the 
ice  pushes  out  laterally  into  the  marginal  lakes  which  develop 
there  or  pushes  up  upon  the  moraines.  It  thus  comes  to 


140        CHARACTERISTICS  OF  EXISTING  GLACIERS 

arrange  its  layers  parallel  to  the  slope  of  the  morainic  sur- 
face or,  in  other  words,  so  that  they  dip  toward  the  ice.44 

Another  type  of  marginal  moraine  which  was  mentioned 
by  Mohn  and  Nansen  from  South  Greenland,  and  later  fully 
described  by  Chamberlin  from  North  Greenland,  is  explained 
by  the  upturning  effect  of  obstructions  in  the  bed,  and  by 
the  shearing  and  overthrusting  movements  which  are  found 
to  exist  in  inland-ice  near  its  margin45  (see  Figs.  83  and  84). 
This  process  has  much  in  common  with  that  which  we  have 
already  described  in  connection  with  scape  colks. 

Fluvio-glacial  Deposits.  —  Where  studied  by  Chamberlin 
near  Inglefield  gulf,  there  appears  to  be  little  or  no  gush- 
ing of  water  from  beneath  the  inland-ice.  Small  streamlets 
only  appeared  beneath  the  ice  border,  bringing  gravel  and 
sand  which  they  distributed  among  the  coarser  morainic 
material.  So  far  as  land  has  been  recently  uncovered  b^^iie 
ice  in  North  Greenland,  and  so  far  as  differentiated  from  the 
topography  of  the  underlying  rock,  it  was  found  to  be  nearly 
plane.  So  far  as  known,  no  eskers  have  been  observed 
about  the  border  of  the  inland-ice  of  Greenland,  and  only 
a  few  irregular  kames  near  Olrik's  bay.46 

REFERENCES 

1  F.  Nansen,  "  The  First  Crossing  of  Greenland,"  vol.  2,  p.  404  ;  R.  E. 
Peary,  "Journeys  in  North  Greenland,"  Geogr.  Jour.,  vol.  II.,  1898,  p.  232. 

2T.  C.  Chamberlin,  "Glacial  Studies  in  Greenland,"  III.,  Jour.  GeoL, 
vol.  3,  1895,  pp.  62-63. 

3  J.  A.  D.  Jensen,  "  Expeditionen  till  Syd-Gronland,  1878,"  Meddelel- 
ser  om  Gronland,  heft  1,  pp.  17-76. 

4  J.  V.  Garde,  "Beskrivelse  of  Expeditionen  til  Sydvest  Gronland,  1893,'' 
Meddelelser  om  Gronland,  heft  16,  1895,  pp.  1-72. 

5  Garde,  I.e.,  pi.  7. 

6 1.  I.  Hayes,  "  The  open  polar  sea,"  London,  1867,  p.  72. 

7H.  Mohn  und  Fridtjof  Nansen,  "  Wissenschaf tlichen  Ergebnisse  von 
Dr.  F.  Nansens  Durchquerung  von  Gronland,  1888,"  Pet.  Mitt.,  Erganz- 
ungsh.,  vol.  105,  1892,  pp.  1-111,  6  pis.,  10  figs.  Especially  Plate  5. 

8  "  Die  Gletscher,"  pp.  105-106. 

9  R.  E.  Peary,  "A  Reconnoissance  of  the  Greenland  Inland-ice,"  Jour. 
Am.  Geogr.  Soc.,  vol.  19,  1887,  pp.  261-289. 

10  "Iceblink,"  which  has  been  suggested  by  some  writers,  is  a  term  gen- 


THE  CONTINENTAL  GLACIER  OF  GREENLAND       141 

erally  applied  among  navigators  to  describe  the  appearance  of  ice  on  the 
horizon,  and  is  contrasted  with  "land  blink,"  which  describes  the  peculiar 
loom  of  the  land.  In  order  to  apply  the  term  to  the  inland-ice  without 
confusion,  it  is,  therefore,  better  to  retain  the  Danish  form  of  the  word. 

11  Petermann  Peak  near  Franz  Josef  fjord  on  the  east  coast,  which, 
according  to  Nansen,  has  an  estimated  height  of   11,000-14,000  feet, 
has  recently  been  shown  to  be  not  more  than  half  that  height    (A.  G. 
Nathorst,  Pet.  Mitt.,  vol.  46,  1899,  p.  242). 

12  A.  G.  Nathorst,  "Den  svenska  expeditionen  till  nordostra  Gronland," 
1899,   Ymer,  vol.  20,  1900,  map  11. 

13  A.  Helland,  "On  the  Ice  Fjords  of  North  Greenland  and  on  the  Forma- 
tion of  Fjords,  Lakes,  and  Cirques  in  Norway  and  Greenland,"  Quart. 
Jour.  Geol.  Soc.,  vol.  33,  1877,  pp.  142-176. 

14  E.  von  Drygalski,  "Gronland-Expedition,"  vol.  1,  1897,  Map  7. 

15  R.  E.  Peary,  "Journey  in  North  Greenland,"  Geogr.  Jour.,  vol.  11, 
1898,  pp.  213-240. 

16  T.  C.  Chamberlin,  "Glacial  Studies  in  Greenland,  III.,"  Jour.  Geol., 
vol.  3,  1895,  p.  61. 

17  Lieut.  A.  Trolle,   "The  Danish  Northeast  Greenland  Expedition," 
Scot.  Geogr.  Mag.,  vol.  25,  1909,  pp.  57-70,  map  and  illustrations. 

18  Chamberlin,  Jour.  Geol.,  vol.  3,  1895,  p.  566.      Salisbury,  ibid.,  vol.  4, 
li§«,  p.  778. 

19  Gunnar  Andersson,  .' '  Danmarks  expeditionen  till  Gronlands  nordost- 
kust,"  Ymer,  vol.  28,  1908,  pp.  225-239,  maps  and  7  figures. 

20  To  the  south  of  the  upper  Nugsuak  Peninsula  in  latitude  70°  10'  N. 

21  R.  S.  Tarr,  "The  Margin  of  the  Cornell  Glacier,"  Am.  Geologist,  vol. 
20,  1897,  pp.  139-156,  pis.  6-12. 

22  Jour.  Am.  Geogr.  Soc.,  vol.  19,  1887,  p.  277. 

23  Garde,  I.e.,  pi.  IV.     See  also  J.  A.  D.  Jensen,  "Expeditionen  till  Syd- 
Gronland,  1878,"  Meddelelser  om  Gronland,  heft  1,  pi.  ii. 

24  Garde,  I.e.,  pi.  V. 

25  Geogr.  Jour.,  vol.  11,  1898,  pp.  217,  218. 

26  Geogr.  Jour.,  I.e.,  p.  232. 

27  E.  von  Drygalski,  "Die  Eisbewegung,  ihre  physikalischen  Ursachen 
und  ihre  geographischen  Wirkungen,"  Pet.  Mitt.,  vol.  44,  1898,  pp.  55-64. 

28  "Glacial  Studies  in  Greenland,  III.,"  Jour.  Geol.,  vol.  3,  1895,  p.  63. 

29  Geogr.  Jour.,  vol.  11,  1898,  p.  215.    See  also  his  map,  Bull.  Am.  Geogr. 
Soc.,  vol.  35,  1903,  p.  496. 

30  Geogr.  Jour.,  vol.  11,  p.  232. 

31  Jour.  Am.  Geogr.  Soc.,  vol.  19,  1887,  p.  269. 

32  "  Gronland-Expedition,"  I.e.,  map  7. 

33  Lieut.  C.  Ryder  in  1886.     Helland  on  a  glacier  of  the  Jakobshavnf  jord 
found  a  rate  of  64  feet  daily. 

34  E.  von  Drygalski,  "Die  Bewegung  des  antarktischen  Inlandeises," 
Zeitsch.  f.  Gletscherk,  vol.  1,  1906-7,  pp.  61-65. 

35  Ed.  Suess,  "Face  of  the  Earth,"  vol.  2,  1888  (translation,  1906),  pp. 
342-344. 


142        CHARACTERISTICS  OF  EXISTING  GLACIERS 

36  Suess,  I.e.,  pp.  337-346. 

37  E.  C.  Case,  "Experiments  in  Ice  Motion,"  Jour.  GeoL,  vol.  3,  1895,  pp. 
918-934. 

38  "Die  Gletscher,"  1904,  p.  171,  fig.  28. 

39  "Recent  Glacial  Studies  in  Greenland."     Annual  address  of  the  Presi- 
dent of  the  Geological  Society  of  America,  Bull.  Geol.  Soc.  Am.,  vol.  6, 
1895,  pp.  199-220,  pis.  3-10. 

40  Chamberlin,  I.e.,  p.  205. 

41  Mohn  u.  Nansen,  "  Wissenschaf tlichen  Ergebnisse  von  Dr.  F.  Nan- 
sen's  Durchquerung  von  Gronland,  1888,"  Pet.  Mitt.,  Erganzungsh.,  vol. 
105,  1892,  p.  91. 

42  R.  S.  Tarr,  "The  Margin  of  the  Cornell  Glacier,"  Am.  GeoL,  vol.  20, 
1897,  p.  148. 

43  "Gronland  Expedition,"  I.e. 

44  von  Drygalski,  I.e.,  p.  529. 

45  Chamberlin,  I.e.,  p.  92. 

46  Salisbury,  I.e.,  p.  809. 


CHAPTER  IX 
NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE 

Few  and  Inexact  Data.  —  The  problems  involving  the 
gains  and  the  losses  of  the  inland-ice  of  Greenland  require 
for  their  satisfactory  solution  a  much  larger  body  of  exact 
data  than  we  now  possess.  Barring  a  few  scattered  and  not 
always  exact  or  reliable  observations,  we  are  practically 
without  knowledge  of  the  amount  or  the  variations  of  atmos- 
pheric pressure,  or  of  snowfall  away  from  the  coastal  areas 
of  the  continent.  Even  within  these  marginal  zones,  the 
losses  from  ablation  and  through  the  calving  of  bergs,  have 
been  estimated  by  crude  methods  only.  Again,  the  great 
height  of  the  ice  surface  within  the  central  plateau,  and  the 
lack  of  any  knowledge  of  the  elevation  of  the  land  surface 
in  those  regions,  has  raised  questions  concerning  the  con- 
ditions of  flow  and  of  fusion  upon  the  bottom  which  will 
probably  long  remain  subjects  of  controversy. 

An  international  cooperative  undertaking  with  one  or 
more  stations  established  in  the  interior  at  points  where 
altitude  has  been  determined  by  other  than  barometric 
methods,  and  with  coast  stations  maintained  contempo- 
raneously and  for  a  period  of  at  least  a  year,  particularly 
if  they  could  be  supplemented  by  balloon  or  kite  observa- 
tions, would  yield  results  of  the  very  greatest  importance.1 
The  Greenland  ice  having  shrunk  greatly  since  the  Pleis- 

143 


144         CHARACTERISTICS  OF  EXISTING  GLACIERS 

tocene  period,  it  is  almost  certain  that  its  alimentation  to- 
day does  not  equal  the  losses  which  it  suffers  along  its  mar- 
gins—  which  in  but  slightly  altered  form  applies  to  the 
Antarctic  continental  glacier  as  well. 

Snowfall  in  the  Interior  of  Greenland.  —  Almost  the  only 
data  upon  this  subject  are  derived  from  a  rough  section  of 
the  surface  layers  of  snow,  as  this  was  determined  by  Nansen 
with  the  use  of  a  staff  near  the  highest  point  in  his  journey 
across  the  inland-ice  along  the  64th  parallel.  At  elevations 
in  excess  of  2270  meters  Nansen  found  the  surface  snow 
"  soft  "  and  freshly  fallen,  but  of  dust  like  fineness.  Be- 
neath the  surface  layer,  a  few  inches  in  thickness  only,  there 
was  a  crust  less  than  an  inch  in  thickness  which  was  ascribed 
to  the  slight  melting  of  the  surface  in  midsummer,2  and  below 
this  crust  other  layers  of  the  fine  "  frost  snow  "  more  and 
more  compact  in  the  lower  portions,  but  reaching  a  thickness 
of  fifteen  inches  or  thereabouts  before  another  crust  and 
layer  was  encountered.3  Other  sections  made  in  like  manner, 
by  pushing  down  a  staff,  revealed  similar  stratification  of 
the  surface  snow  with  individual  layers  never  exceeding 
in  thickness  a  few  feet.  From  these  observations  Nansen 
has  drawn  the  conclusion  that  the  layers  of  his  sections  cor- 
respond to  seasonal  snowfalls,  the  thin  crust  upon  the  sur- 
face of  each  being  due  to  surface  melting  in  the  few  warm 
days  of  midsummer.  He  cites  Nordenskjold  as  believing 
that  the  moist  winds  which  reach  the  continent  of  Greenland 
deposit  most  of  their  moisture  near  the  margin.4 

The  sky  during  almost  the  entire  time  of  the  journey  is 
described  by  Nansen  as  so  nearly  clear  that  the  sun  could 
be  seen,  and  there  were  few  days  in  which  the  sky  was  com- 
pletely overcast.  Even  when  snow  was  falling,  which  often 
happened,  the  falling  snow  was  not  thick  enough  to  pre- 
vent the  sun  showing  through.  This  clearly  indicates  that 
the  snow  falls  from  layers  of  air  very  near  the  snow  surface 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE      145 

below.  The  particles  which  fell  were  always  fine,  like  frozen 
mist  —  what  in  certain  parts  of  Norway  is  known  as 
"  frost  snow  ";  that  is,  snow  which  falls  without  the  mois- 
ture first  passing  through  the  cloud  stage.5 

The  air  temperatures,  even  in  August  and  September, 
when  the  crossing  was  made,  were  on  the  highest  levels 
seldom  much  above  the  zero  of  the  Fahrenheit  scale,  and  at 
night  they  sank  by  over  40°  F.  (in  one  case  to  —  50°  F.). 

Peary,  while  on  the  inland-ice  in  North  Greenland  in  the 
month  of  March,  1894,  registered  on  his  thermograph  a 
temperature  of —  66°  F.,  and  several  of  his  dogs  were  frozen 
as  they  slept.6  The  high  altitudes  and  the  general  absence 
of  thick  clouds  over  the  inland-ice  permit  rapid  radiation, 
so  that  cold  snow  wastes  and  hot  sand  deserts  have  in  com- 
mon the  property  of  wide  diurnal  ranges  of  temperature. 
The  poverty  of  the  air  over  the  inland-ice  in  its  content  of 
carbon  dioxide,  as  shown  by  the  analysis  of  samples  collected 
by  Nansen,  must  greatly  facilitate  this  daily  temperature 
change.7 

From  studies  in  the  Antarctic  it  is  now  known  that  most 
of  the  snow  falls  there  in  the  summer  season,  and  that  little, 
if  any,  moisture  can  reach  the  interior  from  surface  winds. 
The  same  is  probably  true  also  of  the  interior  of  Greenland. 

Though  the  absolute  humidity  of  the  air  upon  the  ice 
plateau  of  Greenland  is  always  low,  the  relative  humidity 
is  large,  and  never  below  73  per  cent  of  saturation  in 
the  levels  above  1000  metres.  Evaporation  occurs  chiefly 
when  the  sun  is  relatively  high,  and  when  the  air  is  again 
chilled,  the  abstracted  moisture  is  returned  to  the  surface  in 
the  form  of  the  almost  daily  snow  mists  or  frost  snow.  The 
observations  went  to  show  that  only  in  the  warmest  days 
of  summer  do  the  sun's  rays  succeed  in  melting  a  very  thin 
surface  layer  of  the  snow.  Of  the  thirty  days  that  Nan- 
sen's  party  was  at  altitudes  in  excess  of  1000  metres,  on 


146         CHARACTERISTICS  OF  EXISTING  GLACIERS 

only  six  is  a  definite  snowfall  reported.  Within  the  in- 
terior of  Greenland  it  appears  that  no  snow  whatever  is  per- 
manently lost  from  the  surface  by  melting* 

While  the  relative  humidity  of  the  air  over  the  central 
plateau  is  so  high,  the  absolute  humidity  is  extremely  low, 
being  measured  from  1.4  mm.  to  4  mm.,  though  generally 
much  below  the  maximum  value.  The  average  absolute 
humidity  was  2.5  mm.,  while  the  average  relative  humidity 
was  92  per  cent.9 

It  has  been  claimed  by  von  Drygalski  that  the  eastern 
portion  of  the  Greenland  ice  sheet  is  a  great  nourishing 
region,  while  the  western  slope,  on  the  other  hand,  is  the 
locus  of  excessive  melting  and  discharge.  In  support  of 
this  view  he  adduces  chiefly  the  admitted  lack  of  symmetry 
of  the  ice  mass.10  So  far  as  alimentation  is  concerned,  the 
view  does  not  seem  to  be  as  yet  supported  by  any  observa- 
tions, and  it  can  hardly  be  regarded  as  a  tenable  hypothesis. 

The  Circulation  of  Air  over  the  Isblink.  —  No  exact  data 
upon  atmospheric  pressures  are  as  yet  available,  except  from 
stations  near  the  sea  level,  mainly  along  the  western  and 
northern  coasts.  Until  stations  have  been  maintained 
for  a  more  or  less  protracted  period  within  the  interior  of 
Greenland,  none  can  be  expected.  None  the  less,  upon 
the  basis  of  the  observed  winds  in  those  portions  of  Green- 
land which  have  been  traversed,  it  may  be  safely  asserted 
that  a  fixed  area  of  high  atmospheric  pressure  is  centered 
over  the  Greenland  isblink,  and  that  the  cold  surface  of 
this  mass  of  ice  is  directly  responsible  for  its  location  there. 
Nansen,  as  early  as  1890,  announced  this  fact,  having 
observed  "  that  the  winds  which  prevail  on  the  coasts 
have  an  especial  tendency  to  blow  outwards  at  all  points."11 
After  many  years  of  experience  in  different  portions  of 
Greenland,  Peary  stated  the  law  of  air  circulation  above  the 
continent  in  clear  and  forceful  language:12  — 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE     147 

Except  during  atmospheric  disturbances  of  exceptional  mag- 
nitude, which  cause  storms  to  sweep  across  the  country  against  all 
ordinary  rules,  the  direction  of  the  wind  of  the  " Great  Ice"  of 
Greenland  is  invariably  radial  from  the  centre  outward,  normal 
to  the  nearest  part  of  the  coast-land  ribbon.  So  steady  is  this  wind 
and  so  closely  does  it  adhere  to  this  normal  course,  that  I  can  liken 
it  only  to  the  flow  of  a  sheet  of  water  descending  the  slopes  from 
the  central  interior  to  the  coast.  The  direction  of  the  nearest  land 
is  always  easily  determinable  in  this  way.  The  neighborhood  of 
great  fjords  is  always  indicated  by  a  change  in  the  wind's  direction ; 
and  the  crossing  of  a  divide,  by  an  area  of  calm  or  variable  winds, 
followed  by  winds  in  the  opposite  direction,  independent  of  any 
indications  of  the  barometer. 

Except  for  light  sea  breezes  blowing  on  to  the  land  in 
February,  the  Danish  Northeast  Greenland  expedition  found 
"  the  wind  was  constantly  from  the  northwest,  this  being 
the  result  of  the  high  pressure  of  air  which  is  found  over 
the  inland  ice." 13 


FIG.  85.  —  Diagram  to  illustrate  the  air  circulation  over  the  isblink  of  Greenland. 

These  conditions  of  circulation  are  schematically  repre- 
sented in  Fig.  85.  In  March,  1894,  Peary  encountered  on 
the  north  slope  of  the  inland-ice  a  series  of  blizzards  before 
unprecedented  in  Arctic  work,  one  lasting  for  three  days, 
during  which  for  a  period  of  34  hours  the  average  wind  ve- 
locity, as  recorded  by  anemometer,  was  48  miles  per  hour. 
Viewed  in  the  light  of  the  violent  southerly  blizzards  which 
Shackelton  found  to  prevail  upon  the  ice  plateau  in  the 
Antarctic,  these  winds  must  be  considered  as  belonging  to 


148        CHARACTERISTICS  OF  EXISTING  GLACIERS 

the  same  Greenland  or  isblink  system  which  has  been  de- 
scribed as  of  such  general  prevalence. 

After  comparing  the  meteorological  data  from  his  journey 
with  contemporaneous  observations  on  the  shores  of  Baffin's 
Bay,  Nansen  believed  that  he  was  able  to  make  out  faintly 
the  influence  of  general  cyclonic  movements.  He  says:14 — 

The  plateau  seems  to  be  too  high  and  the  air  too  cold  to  allow 
depressions  or  storm  centres  to  pass  across,  though,  nevertheless, 
our  observations  show  that  in  several  instances  the  depressions  of 
Baffin's  Bay,  Davis'  Strait,  and  Denmark's  Strait,  can  make  them- 
selves felt  in  the  interior. 

This,  it  must  be  remembered,  was  in  the  narrow  southern 
extension  of  the  continent  and  essentially  marginal  to  the 
main  ice  mass.  Commenting  upon  Peary's  conclusions 
above  quoted,  Chamberlin 15  ascribes  the  wind  which  flows 
downward  and  outward  from  the  isblink  to  a  notable 
increase  of  its  specific  gravity  through  contact  with  and 
consequent  cooling  by  the  snow  surface.16 

It  is  perhaps  well  to  here  allude  to  the  conditions  under 
which  heat  is  added  to  or  abstracted  from  fluid  masses, 
whether  they  be  liquid  or  gaseous.  Communication  is  by 
contact,  and  distribution  by  the  process  known  as  convec- 
tion—  adjustments  of  position  due  to  changes  in  specific 
gravity  resulting  from  change  of  temperature.  These  con- 
vection currents  must  be  started  either  by  rendering  the 
upper  layers  heavier,  or  the  lower  layers  lighter,  than  they 
were  when  in  equilibrium.  No  distributing  convection 
currents  can  be  set  up  by  heating  (making  lighter)  at  the 
top,  or  by  cooling  (making  heavier)  at  the  bottom;  and 
so  long  as  confined,  no  motions  of  any  kind  can  thus  be 
initiated.  Water  may  be  boiled  in  the  upper  layers  within 
a  test-tube,  or  frozen  in  the  lower  layers,  without  disturb- 
ing the  conditions  of  equilibrium. 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE      149 

Now  it  is  at  the  bottom  that  the  air  above  the  isblink 
is  cooled  by  contact;  and  it  is  due  to  the  peculiar  shield- 
like  form  of  this  ice  mass  that  the  heavier  cooled  bottom 
layer  is  able  to  slide  off  radially  as  would  a  film  of  oil  from 
a  model  of  similar  form.  The  centrifugal  nature  of  this 
motion  tends  to  produce  a  vacuum  above  the  central  area 
of  the  ice  mass,  and  air  must  be  drawn  down  from  the 
upper  layers  of  the  atmosphere  in  order  to  supply  the  void. 
It  is  here  that  is  located  the  "  eye  "  of  the  anticyclone. 

Foehn  Winds  within  the  Coastal  Belt. --The  sliding 
down  of  masses  of  heavy  air  upon  the  snow  surface  of  the 
Greenland  ice  must  bring  about  adiabatic  heating  of  the 
air  and  a  consequent  elevation  of  the  dew  point.  The  in- 
crease of  temperature  being  about  1°  C.  for  every  100  metres 
of  descent,  a  rise  of  temperature  of  as  much  as  20°  C.  or  36° 
F.  will  result  in  a  descent  from  the  summit  of  the  plateau, 
assuming  this  to  have  an  elevation  of  10,000  feet.  Some 
reduction  in  the  amount  of  this  change  of  temperature  will, 
of  course,  result  from  the  contact  of  the  air  with  the  cold 
snow  surface  during  its  descent,  this  modification  being 
obviously  dependent  upon  the  velocity  of  the  current. 
The  warm,  dry  winds  which  in  different  districts  have  been 
described  under  the  names  foehn  and  chinook  are  the  inev- 
itable consequence  of  such  conditions,  and  are,  moreover, 
particularly  characteristic  of  steep  mountain  slopes  more 
or  less  covered  by  glaciers.  Such  foehn  winds  have  long 
been  recognized  as  especially  characteristic  of  western 
Greenland.  Dr.  Henry  Rink,  who  was  a  pioneer  in  the 
scientific  study  of  Greenland,  referring  to  these  winds, 
wrote  in  1877 : 17  - 

Among  the  prevailing  winds  in  Greenland  the  warm  land  wind 
is  the  most  remarkable.  Its  direction  varies  according  to  locality 
from  true  E.S.E.  to  E.N.E.  always  proceeding  though  warm  from 
the  ice-covered  interior,  and  generally  following  the  direction  of 


150        CHARACTERISTICS  OF  EXISTING  GLACIERS 

the  fjord.  It  blows  as  frequently  and  as  violently  in  the  north 
as  in  the  south,  but  more  especially  at  the  fjord  heads,  while  at 
the  same  time  in  certain  localities  it  is  scarcely  perceptible.  It 
often  turns  into  a  sudden  gale;  the  squalls  in  some  fjords  rushing 
down  between  the  high  rocks,  in  certain  spots  often  sweep  the 
surface  of  the  water  with  the  force  of  a  hurricane,  raising  columns 
of  fog,  while  the  surrounding  surface  of  the  sea  remains  smooth. 

Nansen  encountered  one  of  these  foehn  winds  on  his  de- 
scent, and  Peary  mentions  their  occurrence  in  the  north. 
In  Scoresby's  Land  on  the  east  coast,  a  foehn  wind  in  the 
winter  season  has  been  known  in  a  single  hour  to  change 
the  temperature  by  24°  C.  (or  43°  F.),  and  the  maximum 
change  during  such  a  wind  is  far  greater.  It  is  not  yet 
known  from  observations  to  what  distance  above  the  ice 
surface  the  winds  of  the  Greenland  system  extend,  or  how 
the  broad  cyclonic  areas  of  the  atmosphere  are  modified. 
The  anti-cyclone  of  the  continent  is,  however,  none  the  less 
clear  and  constant  and  is  centred  over  the  high  interior. 
Nansen  has  remarked  the  calms  over  the  divide  of  his 
section.18 

There  is  some  evidence  that  in  adopting  the  important 
modern  laws  of  adiabatic  cooling  of  the  air,  we  have  allowed 
the  pendulum  to  swing  too  far,  and  have  given  too  little 
weight  to  the  effect  of  cooling  through  contact  of  air  with 
either  rock  or  snow.  The  latest  results  of  Antarctic  ex- 
peditions furnish  the  most  striking  proof  of  this,  if  other  than 
Greenland  examples  were  needed,  and  the  Antarctic  studies 
throw  much  light  upon  the  conditions  of  snow  distribution 
which  are  observed  in  Greenland. 

Wind  Transportation  of  Snow  over  the  Desert  of  Inland- 
ice. —  Whymper  and  Nordenskjold  each  called  Greenland 
a  "  Northern  Sahara."  In  different  ways  Nansen  and  Peary 
have  also  instituted  comparisons  between  the  wastes  of  snow 
in  the  interior  of  Greenland  and  the  desert  of  sand  of  the 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE      151 

Sahara.  The  Norwegian  explorer  has  emphasized  especially 
the  wide  daily  ranges  of  temperature,  which  because  of 
generally  cloudless  atmospheres,  both  deserts  have  in  com- 
mon. Of  the  monotonous  and  elemental  simplicity  of  the 
snow  vistas  back  from  the  ice  margin  in  North  Greenland, 
Peary  says:19  — 

It  is  an  Arctic  Sahara,  in  comparison  with  which  the  African 
Sahara  is  insignificant.  For  on  this  frozen  Sahara  of  inner  Green- 
land occurs  no  form  of  life,  animal  or  vegetable ;  no  fragment  of 
rock,  no  grain  of  sand  is  visible.  The  traveller  across  its  frozen 
wastes,  travelling  as  I  have  week  after  week,  sees  outside  himself 
and  his  own  party  but  three  things  in  all  the  world,  namely,  the 
infinite  expanse  of  the  frozen  plain,  the  infinite  dome  of  the  cold 
blue  sky,  and  the  cold  white  sun  —  nothing  but  these  (see  Fig.  86). 


FIG.  86.  —  On  the  Sahara  of  snow  (after  Peary). 

There  is,  however,  yet  another  marked  parallel  between 
the  snow  waste  and  the  sand  desert.  It  is  the  importance 
of  wind  as  a  transporting  agent.  In  his  shorter  acquaintance 


152        CHARACTERISTICS  OF  EXISTING  GLACIERS 

with  southern  Greenland  Nansen  was  less  impressed  with 
this.,  but  he  has  explained  the  secondary  snow  ridges  upon 
the  marginal  terraces  of  the  inland-ice  as  wind  accumula- 
tions.20 These  long  parallel  ranges  of  snow  drift  thus  cor- 
respond to  the  similar  ranges  of  sand  dunes  which  some- 
times throughout  a  width  of  many  miles  hem  in  the  deserts 
of  lower  latitudes.  In  northern  Greenland  Peary's  observa- 
tions have  a  special  value.  He  says: 21  — 

There  is  one  thing  of  especial  interest  to  the  glacialist  —  the 
transportation  of  snow  on  the  ice-cap  by  the  wind.  .  .  . 

The  opinion  has  been  forced  upon  me  that  the  wind,  with  its 
transporting  effect  upon  the  loose  snow  of  the  ice-cap,  must  be 
counted  as  one  of  the  most  potent  factors  in  preventing  the  increase 
in  height  of  the  ice-cap  —  a  factor  equal  perhaps  to  the  combined 
effects  of  evaporation,  littoral  and  subglacial  melting,  and  glacial 
discharge.  I  have  walked  for  days  in  an  incessant  sibilant  drift 
of  flying  snow,  rising  to  the  height  of  the  knees,  sometimes  to  the 
height  of  the  head.  If  the  wind  becomes  a  gale,  the  air  will  be 
thick  with  the  blinding  drift  to  the  height  of  100  feet  or  more.  I 
have  seen  in  the  autumn  storms  in  this  region  round  an  amphi- 
theatre of  some  15  miles,  snow  pouring  down  in  a  way  that  reminds 
one  of  Niagara.22  When  it  is  remembered  that  this  flow  of  the  at- 
mosphere from  the  cold  heights  of  the  interior  ice-cap  to  the  lower 
land  of  the  coast  is  going  on  throughout  the  year  with  greater  or 
less  intensity,  and  that  a  fine  sheet  of  snow  is  being  thus  carried 
beyond  the  ice-cap,  to  the  ice-free  land  at  every  foot  of  the  periphery 
of  the  ice-cap,  it  will  perhaps  be  seen  that  the  above  assumption 
is  not  excessive.  I  feel  confident  that  an  investigation  of  the  actual 
amount  of  this  transfer  of  snow  by  the  wind  is  well  worth  the 
attention  of  all  glacialists. 

Fringing   Glaciers   Formed   from   Wind   Drift.  —  In   the 

vicinity  of  Inglefield  Gulf  in  northwest  Greenland,  the  inland- 
ice  ends  in  a  steep,  snowy  slope  rising  to  a  height  of  about 
100  feet,  where  is  a  terminal  moraine,  above  which  moraine 
rises  the  great  dome  of  the  inland-ice.  The  whiteness  and 
freshness  of  a  portion  of  the  snow  of  the  outer  border,  when 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE      153 

examined  by  Chamberlin,23  showed  it  to  be  wind  drift  of 
recent  accumulation.  Locally,  however,  older  and  discol- 
ored snow  appeared  beneath  the  whiter  surface  snow,  and 
in  a  few  places  stratified  granular  ice  with  some  included 
rock  debris.  This  snow  and  ice  becomes  augmented  from 
year  to  year  and  is,  in  Chamberlin 's  opinion,  a  species  of 
fringing  glacier.  Such  fringes  were  from  a  few  rods  to  a 
half  mile  in  breadth,  and  where  a  favorable  depression  ex- 
isted, one  was  observed  extending  for  a  mile  or  more  down 
the  valley.  Commander  Peary  has  found  this  a  dominant 
feature  on  the  north  Greenland  coast.  Fringing  glaciers 
of  this  type  have  also  been  described  by  Salisbury  from 
the  vicinity  of  Melville  Bay.  Their  movement  was  clearly 
evinced  by  their  structure  and  by  the  debris  which  they 
carried.24 

Nature  of  the  Surface  Snow  of  the  Inland-ice.  —  The 
surface  snow  from  the  marginal  zones  of  the  inland-ice 
has  the  granular  form  characteristic  of  neves,  as  has 
been  shown  with  exceptional  clearness  in  elaborate  studies 
by  von  Drygalski.25  Such  grains,  grown  by  accretions 
from  a  single  crystal  nucleus  and  at  the  expense  of  neigh- 
boring crystals,  must  require  either  fusion  from  tem- 
porary elevation  of  temperature,  or  from  pressure.  The 
observations  of  von  Drygalski  were  made  on  the  ice  of  the 
marginal  tongues  and  on  the  blue  layers  of  the  inland-ice; 
but  as  the  samples  taken  farthest  from  the  margins  were 
found  at  a  height  of  only  500  meters,  the  results  throw 
little  light  upon  the  conditions  of  surface  snow  within  the 
interior,  where  melting  does  not  take  place.  In  view  of 
Nordenskj  old's  observations  in  Spitzbergen 26  and  recent 
studies  in  Antarctica  it  is  unlikely  that  firn  or  neVe  snow 
will  be  found  within  the  interior  except  at  some  depths  below 
the  surface. 

Nansen  has  described  the  fine  "  frost  snow  "  which  falls 


154        CHARACTERISTICS  OF  EXISTING  GLACIERS 

almost  daily  from  an  air  layer  near  the  snow  surface,  from 
which  its  moisture  has  been  derived.  Melting  does  not 
occur  there,  as  already  stated,  except,  perhaps,  for  a  few 
days  in  the  height  of  summer  when  a  thin  crust  develops 
upon  the  surface.27  Peary  has  referred  to  the  snow  at 
the  highest  altitudes  which  he  reached  in  north  Green- 
land as  "unchanging  and  incoherent. "  This  dry  hard 
snow  chased  by  the  wind,  has  the  cutting  effect  of  sand 
in  a  blast,  and  thus  is  offered  still  another  parallel  with 
deserts  and  their  wind  blown  sand.  Each  new  storm,  we 
are  told  by  Stein,28  piles  up  a  snowbank  on  the  lee  sides 
of  nunataks,  but  the  next  storm,  coming  from  a  somewhat 
different  direction  and  laden  with  fine  hard  snow,  cuts 
away  the  earlier  deposit  as  would  a  sand  blast.  Peary  dis- 
covered one  of  his  earlier  snow  huts  partly  cut  away  by 
this  process. 

Snow  Drift  Forms  of  Deposition  and  Erosion — Sastrugi. — 
The  minor  inequalities  of  the  snow  surface  as  determined 
by  the  wind  blowing  over  the  inland-ice,  have  been  mentioned 
more  or  less  persistently  by  all  Arctic  travellers,  since  upon 
the  character  of  this  surface  has  so  largely  depended  the 
celerity  of  movement  in  sledge  journeys.  It  is  unfortunate 
that  no  one  has  discussed  the  subject  from  a  scientific  stand- 
point, for  it  has  great  significance  in  connection  with  the 
study  of  the  strength  and  direction  of  the  wind  over  the 
snow  surface.  All  minor  hummocks  and  ridges  of  this 
nature  are  included  under  the  general  term  sastrugi  (see  Fig. 
87). 

The  student  may  learn  much  concerning  their  form  within 
the  Antarctic  regions  from  examination  of  the  many  beau- 
tiful photographs  recently  published  by  the  Royal  Society 
in  connection  with  the  British  Antarctic  Expedition.29  On 
plate  92  of  this  collection,  sastrugi  are  shown  which  were 
originally  laid  down  in  "  elongated  domes  "  and  "  crescent 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE     155 

hollows/7  but  which  on  account  of  change  in  the  wind  di- 
rection the  drifting  snow  granules  have  cut  away  both  on 
the  soft  surface  and  in  the  harder  deep  layers.  As  a  result 
of  this  erosion  cross  flutings  have  been  superimposed  upon  the 
original  forms. 

Our  best  study  of  snow  drift  forms  has  been  made  by  Dr. 


FIG.  87.  —  Sastrugi  on  the  inland-ice  of  North  Greenland  (after  Peary). 

Vaughan  Cornish,  who,  after  a  series  of  monographs  dealing 
with  waves  in  other  materials,  has  spent  a  winter  in  Canada 
in  order  to  study  the  phenomena  connected  with  the  drifting 
of  snow.30  It  is  found  that  snow  which  falls  at  temperatures 
near  32°  F.  is  wet  and  sticky,  and  behaves  quite  differently 
from  that  which  falls  near  or  below  the  zero  of  the  same 
scale;  which,  on  the  contrary,  is  dry  and  slippery.  Sub- 
sequent modifications  of  either  of  these  forms  of  snow 
depend  chiefly  upon  pressure,  temperature,  radiation,  and 


156         CHARACTERISTICS  OF  EXISTING  GLACIERS 

wind.  It  is  the  cold,  dry,  and  granular  snow  only  which 
makes  so-called  normal  waves,  and  it  must  be  this  form 
which  plays  the  major  role  in  producing  the  surface  irregu- 
larities of  the  inland-ice  of  Greenland. 

Ripples  and  larger  waves  alike,  when  formed  from  granu- 
lar snow  and  when  shaped  by  wind  accumulation,  have  the 
steep  side  always  to  leeward,  in  which  respect  the  snow 
behaves  like  drifted  sand.  In  order  to  produce  waves  or 
ripples,  the  wind  must  have  a  velocity  sufficient  to  be  thrown 
into  undulations  by  the  irregularities  of  the  surface  over 
which  it  blows.  The  most  perfectly  moulded  forms  are 
naturally  produced  upon  a  relatively  plane  surface,  such  as 
is  realized  on  the  inland-ice  of  Greenland  —  the  "  imperial 
highway  "  of  Commander  Peary. 


FIG.  88.  —  Barchans  in  snow,     a,  of  deposition  ;  6,  of  erosion  (after  Cornish) . 


Apparently  the  direction  of  the  greatest  extension  of  the 
sastrugi  will  depend  upon  the  strength  of  the  wind  and  upon 
the  amount  of  snow  which  is  being  transported,  much  as 
has  been  found  to  be  the  case  with  drifted  sand.31  Thus,  with 
small  amounts  of  snow  and  moderate  winds,  the  character- 
istic form  of  sastrugi  is  a  short,  scalloped  ridge  lying  across 
the  wind  direction  and  in  form  not  unlike  an  ox-yoke  — 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE      157 

something  intermediate  between  a  barchan  and  a  transverse 
ridge.  Barchans  of  snow  almost  identical  in  form  with  sand 
barchans,  are  produced  apparently  under  like  conditions, 
the  chief  differences  being  that  lighter  winds  suffice  to  ac- 
complish the  result  with  the  less  ponderous  snow,  and  that 
the  resulting  forms  set  quicker  in  the  snow  (see  Fig.  88  a). 

Cornish  has  realized  the  full  importance  of  snow-blast 
erosion  in  modifying  the  form  of  snow  drifts.  His  barchans 
of  erosion,  in  plan  resemble  the  barchans  of  deposition  from 
which  they  are  derived,  but  unlike  the  depositional  forms 
their  broader  surface  is  concave  upward  instead  of  convex, 
and  their  steeper  face  is  toward  the  wind  (see  Fig.  88  6). 

Some  facts  of  importance  which  concern  the  density  of  the 
snow  are  emphasized  by  Cornish,  and  apply  with  especial 
force  to  the  surface  snow  of  inland-ice.  It  was  found  that 
crusts  upon  the  surface  of  snow  do  not  necessarily  imply 
melting,  but  are  produced  in  temperatures  below  the  fusion 
point.  When  the  air  temperatures  at  Winnipeg  ranged 
from  25°  to  —  28°  F.  the  snow  surface  over  the  river  set  so 
hard  that  the  moccasined  heel  did  not  dent  it.  Pieces  of  this 
snow  broken  off  and  held  up  to  the  sunlight  showed  a 
"  mosaic  of  small  translucent  icy  blocks  cemented  firmly  by 
opaque  ice."  The  effect  upon  snow  density  of  the  radiation 
from  the  surface  and  of  pressure  from  the  wind,  were  strik- 
ingly brought  out  by  a  number  of  observations.  Newly 
fallen  snow  in  Canada  has  a  density  of  about  0.1.  Over 
the  level  surface  about  Winnipeg  in  the  month  of  January 
and  at  a  temperature  of  10°  F.,  the  snow  was  found  to  have 
a  density  within  the  upper  two  feet  of  0.38;  while  in  the 
woods  at  the  same  time  and  at  the  same  depth,  here  without 
a  crust,  its  density  was  0.19.  Thus  it  is  seen  that  the  snow 
in  the  woods  is  about  twice  as  heavy  as  newly  fallen  snow, 
but  only  about  half  as  heavy  as  that  which  has  been  chased 
about  by  the  wind.  At  Glacier  House  in  the  Selkirks,  where 


158        CHARACTERISTICS  OF  EXISTING  GLACIERS 

the  snow  is  shielded  from  the  wind  within  a  narrow  valley, 
experiments  showed  a  density  of  0.106  at  the  surface,  whereas 
at  a  depth  of  one  foot  below  the  surface  the  density  was 
0.195,  and  at  a  depth  of  four  feet,  1.354.  The  middle  value 
being  that  of  the  snow  in  the  woods  at  Winnipeg,  it  is  seen 
that  the  weight  of  an  additional  three  feet  of  snow  is  neces- 
sary in  order  to  pack  snow  as  tightly  as  is  done  by  the  wind 
blowing  over  the  prairie.  After  a  time,  as  a  result  of  this 
treatment  by  the  wind,  an  eight-inch  snowfall  dwindles  by 
packing  in  the  woods  to  four  inches,  and  over  the  open  plain 
to  a  two-inch  layer.  According  to  Gourdon,  a  cubic  metre 
of  Antarctic  snow  may  exceed  700  kilogrammes  in  weight.32 

In  eroding  a  drift,  the  wind  first  attacks  the  softer  surface 
layer.  This  removed,  the  snow  of  the  blast  adheres  less 
to  the  surface  of  the  drift,  and  in  consequence  abrades  it 
more  vigorously.  Thus,  notches  in  the  ridges,  instead  of 
being  mended  by  the  detritus,  are  increased  by  it,  and  trans- 
verse ridges  are  presently  cut  through,  and  we  pass  by  stages 
from  an  arrangement  of  ridges  transverse  to  the  wind  to  that 
of  longitudinal  structures  having  the  greatest  extension 
parallel  to  the  wind.33  These  longitudinal  sastrugi  appear 
to  be  the  dominant  ones,  and  from  them  the  direction  of 
prevailing  winds  may  be  determined  as  has  been  already 
proven  in  the  Antarctic.  On  the  Siberian  tundras  the 
sastrugi  are  often  the  only  guides  of  direction  which  the 
natives  have.34 

Source  of  the  Snow  in  Cirrus  Clouds.  —  What  has  been 
learned  of  the  circulation  of  air  above  the  continental  ice  of 
Greenland,  makes  it  extremely  unlikely  that  any  such  exces- 
sive alimentation  upon  the  eastern  margin  through  ordinary 
snow  fall,  as  has  been  advocated  by  von  Drygalski,  can 
occur.35  Such  moisture-laden  air  as  can,  under  normal  con- 
ditions, reach  the  interior  plateau  must  descend  from  higher 
levels  in  the  anti-cyclone  above  the  central  boss,  and  be 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE      159 

distributed  by  the  outward  flowing  surface  currents.  From 
such  altitudes  the  moisture  would  probably  be  congealed  in 
the  form  of  fine  ice  needles,  such  as  are  believed  to  exist  in 
cirrus  clouds.  This  ice,  in  descending  to  the  plateau,  would 
be  adiabatically  heated  with,  as  a  consequence,  the  melting 
and  vaporization  of  the  ice  crystals,  which  on  reaching  the 
cold  air  layer  directly  enveloping  the  ice  surface  would  be 
congealed  without  passing  through  the  cloud  stage,  thus 
yielding  the  characteristic  frost  snow.  This  process  will  be 
more  fully  treated  in  part  III,  after  Antarctic  ice  masses 
have  been  considered.  Of  greatest  interest  in  this  connec- 
tion, is  the  observation  of  Nansen  that  while  the  sky  was, 
during  the  time  of  his  crossing,  in  the  main  clear,  those 
clouds  which  were  present  were  generally  either  cirrus  clouds 
or  some  combination  of  cirrus  with  cumulus  and  stratus 
clouds.  No  cumulus  clouds  whatever  were  observed.  In 
tabular  form  his  results  are  as  follows: 


FORM  OF  CLOUDS 

No.  OP  DAYS 

PER  CENT. 

Cirrus                            

23  1 

44 

Cirro-stratus      

17[  51 

33 

Cirro-cumulus  

11 

21 

Cumulo-stratus      

j 
22 

42 

Stratus 

10 

19 

As  already  stated,  such  snow  as  reaches  the  central  area 
must,  it  would  seem,  be  derived  from  the  cirrus  clouds  which 
at  higher  levels  move  in  toward  the  anti-cyclone  and  de- 
scend in  its  center  to  become  outward  flowing  surface  cur- 
rents over  the  "  Great  Ice."  This  subject  will  be  more  fully 
developed  in  connection  with  the  Antarctic  continental  gla- 
cier (Chapter  XVI). 


160        CHARACTERISTICS  OF  EXISTING  GLACIERS 


REFERENCES 

1  Robert  Stein,  "  Suggestion  of  a  Scientific  Expedition  to  the  center  of 
Greenland,"  Congres  Intern,  pour  1'Etude  des  Regions  Polaires,  Brussels, 
1906,  pp.  1-4  (separate). 

2  In  the  light  of  later  studies  this  may  as  satisfactorily  be  explained 
through  hardening  by  the  wind. 

3  Mohn  u.  Nansen,  1.  c.,  p.  86. 

4  Nansen,  L  c.,  vol.  1,  p.  495. 

5  Nansen,  L  c.,  vol.  2,  p.  56. 

6  Geogr.  Jour.,  vol.  11,  1898,  p.  228. 

7  Mohn  u.  Nansen,  L  c.,  pp.  109-111. 

8  Nansen,  L  c.,  vol.  2,  p.  491.   See  also  Peary,  Geogr.  Journ.,  I.  c.,  p.  214. 

9  Mohn  u.  Nansen,  I.  c.,  pp.  44^-45. 

10  E.  v.  Drygalski,  "Die  Eisbewegung,  ihre  physikalischen  Ursachen  und 
ihre  geographischen  Wirkungen,"  Pet.  Mitt.,  vol.  44,  1898,  pp.  55-64.     See 
also  by  the  same  author,  "Gronland-Expedition,"  etc.,  pp.  533-539. 

11  Nansen,  1.  c.,  vol.  2,  p.  496.  Also  Mohn  and  Nansen,  I.  c.,  pp.  44-47. 

12  "Journeys  in  North  Greenland,"  Geogr.  Jour.,  vol.  11,  1898,  pp.  233- 
234.     See  also  "Northward  over  the  'Great  Ice,'"  vol.  1,  pp.  Ixix-lxx. 

"Lieut.  A.  Trolle,  R.  D.  N.,  "The  Danish  Northeast  Greenland  Ex- 
pedition," Scot.  Geogr.  Mag.,  vol.  25,  1909,  pp.  57-70  (map  and  illustra- 
tions). 

14  Nansen,  1.  c.,  vol.  2,  p.  496. 

15  Jour.  Geol,  vol.  3,  1895,  pp.  578-579. 

16  Professor  v.  Drygalski  has  shown  that  on  the  Great  Karajak  glacier 
near  the  coast  in  central  western  Greenland,  the  temperature  of  the  snow 
and  ice  down  to  a  depth  of  60  feet  or  more  undergoes  a  fall  of  tempera- 
ture in  response  to  the  severity  of  the  winter's  cold,  but  in  time  this  fall 
in  temperature  lags  behind  the  period  of  maximum  cold.     Below  that 
depth,  however,  it  approximates  in  temperature  to  the  zero  of  the  centi- 
grade scale.     Temperatures  of  the  snow  measured  just  below  the  surface, 
varied  from  -  11°  to  -  26°  C.      (E.  von  Drygalski,  "Gronland-Expedition 
der  Gesellschaft  fur  Erdkunde  zu  Berlin,"  1891-1893,  vol.  1,  1897,  pp. 
470-472.) 

17  Henry   Rink,    "Danish   Greenland,  Its  People  and   Its  Products,'* 
London,  1877,  p.  468. 

18  Nansen,  I.  c.,  vol.  2,  pp.  487-488,  496. 

19  Geogr.  Journ.,  I.  c.,  pp.  214,  215.  . 

20  Mohn  u.  Nansen,  I.  c.,  p.  78. 

21  Geogr.  Jour.,  L  c.,  pp.  233-234. 

22  See  Nordenskjdld  ante,  p.  114. 

23  T.  C.  Chamberlin,   "Glacial  Studies  in  Greenland,  VI.,"  Jour.  Geol., 
vol.  3,  1895,  pp.  580-581. 

24  Salisbury,  Jour.  Geol.,  vol.  3,  p.  886. 

25  "Gronland-Expedition,"  etc.,  vol.  1,  1897.     See  also  C.  H.  Ryder, 


NOURISHMENT  OF  THE  GREENLAND  INLAND-ICE     161 

Undersogelse  af  Gronlands  vestkyst  fra  72°  till  74°  35',  1886-1887,  Med- 
delelser  om  Gronland,  heft  8,  pi.  xvii. 

26  A.  E.  Nordenskjold,  "  Die  Schlittenfahrt  der  Schwedischen  Expedition 
im  nordostlichen  Theile  von  Spitzbergen,"  24  April-15  Juni,  Pet.  Mitt., 
vol.  19,  1873,  pp.  450-453. 

27  "Thus  it  will  be  seen  that  at  no  great  distance  from  the  east  coast 
the  surface  of  dry  snow  begins,  on  which  the  sun  has  no  other  effect  than 
to  form  a  thin  crust  of  ice.     The  whole  of  the  surface  of  the  interior  is 
entirely  the  same."     (Nansen,  1.  c.,  vol.  2,  p.  478.) 

28  Robt.  Stein,  Congres  international  pour  1'etude  des  regions  polaires, 
Brussels,  1906,  pp.  1-4  (separate). 

29  National  Antarctic  Expedition,  1901—4.     Album  of  photographs  and 
sketches  (with  brief  descriptions,  Ed.),  London,  1908. 

^Vaughan    Cornish,   "On  Snow-waves  and  Snow-drifts  in  Canada," 
Geogr.  Jour.,  vol.  20,  1902,  pp.  137-175. 

31  P.   N.   Tschirwinsky,   "Schneedunen  und   Schneebarchane  in  ihrer 
Beziehungen  zu  aolischen  Schneeablagerungen  im  Allgemeinen,"  Zeitsch. 
f.  Gletscherk.,  vol.  2,  1907,  pp.  103-112. 

32  E.  Gourdon,  Expedition  Antarctique  Francaise,  1903-1905,  Glaciologie, 
Paris,  1908,  p.  75. 

33  Cornish,  I.  c.,  pp.  159-160. 

34  Tschirwinsky,  1.  c.,  p.  107. 

35  "The  east  is  to  be  regarded  as  the  region  of  origin  of  snow,  the  west 
as  the  terminal  region  of  the  Greenlandic  glaciation."     (E.  von  Dry- 
galski,  "Die  Eisbewegung,  ihre  physikalischen  Ursachen  und  ihre  geo- 
graphischen  Wirkungen,"  Pet.  Mitt.,  vol.  44,  1898,  pp.  55-64.) 


CHAPTER  X 

DEPLETION    OF    THE    GREENLAND    ICE    FROM    SURFACE 

MELTING 

Eastern  and  Western  Slopes  Compared. --Though  it  is 
probably  not  true,  as  has  been  claimed  by  von  Drygalski, 
that  the  eastern  border  of  the  continent  is  the  locus  of 
nourishment  for  the  ice,  it  is  almost  certain  that  the  losses 
are  much  greater  along  the  western  margins.  For  this  there 
are  several  reasons.  In  the  first  place,  the  eastern  base  is 
apparently  characterized  by  lower  temperatures.  The  cold 
ocean  current,  which  carries  ice  bergs  and  floes  from  the 
Arctic  Ocean  southward  in  Baffin's  Bay,  follows  the  western 
shore,  while  a  warmer  counter  current  flows  northward  along 
the  eastern  or  Greenland  coast  at  least  in  its  southern 
stretches.  Tarr  thinks  this  current  may  reach  as  far  as 
Melville  Bay.1 

Again,  ablation  or  surface  melting  is  to  a  large  extent 
dependent  upon  the  quantity  of  rock  debris  which  is  blown 
onto  the  ice  surface  from  its  margins.2  In  southern  Green- 
land, at  least,  the  wider  ribbon  of  exposed  shore  land  upon 
the  western  coast  conspires  with  the  prevailing  westerly  winds 
to  make  a  more  effective  marginal  attack  upon  the  anti- 
cyclone of  the  continent.  Nansen  reports  that  he  found  on 
the  east  coast  none  of  the  rock  dust  first  described  by 
Nordenskjold  as  "  cryoconite,"  though  it  extended  inward 
from  the  western  coast  as  much  as  30  kilometres.3 

162 


DEPLETION  OF  THE  GREENLAND   ICE  163 

Still  further  it  is  to  be  remembered  that  the  ice  of  the 
west  margin  is  intersected  by  many  deep  fjords,  which 
communicating  with  the  open  sea,  remove  an  enormous 
quantity  of  ice  in  the  form  of  bergs.  Upon  the  eastern 
coast,  the  pack-ice  prevents  the  removal  of  bergs  except 
from  the  southern  latitudes. 

Effect  of  the  Warm  Season  Within  the  Marginal  Zones  of 
the  Inland-ice.  —  In  winter  the  entire  surface  of  the  ice,  and 
the  border  of  the  land  as  well,  are  covered  with  an  un- 
broken layer  of  fine,  dry  snow.  The  suddenness  of  the 
change  to  summer  within  the  land  zone  outside  the  ice 
front  has  been  emphasized  by  Trolle.  The  temperature  of 
the  snow  upon  the  land  in  northeast  Greenland  rose  gradu- 
ally with  the  arrival  of  summer  until  the  melting-point  was 
reached,  and  then  in  one  day  all  the  snow  melted.  "  The 
rivers  were  rushing  along,  flowers  were  budding  forth,  and 
in  the  air  the  butterflies  were  fluttering.7' 4 

The  snow  upon  the  surface  of  the  inland-ice,  where  studied 
by  von  Drygalski  within  the  western  marginal  zone,  was 
found  to  have  temperatures  which  in  the  winter  season  were 
normally  lowest  just  below  the  surface,  and  which  approxi- 
mated to  the  zero  of  the  centigrade  scale  at  depths  of  gener- 
ally a  few  metres  only.  In  October  with  a  sub-surface 
temperature  of  —11°  C.  the  zone  of  zero  temperature  was 
reached  at  a  depth  of  a  little  more  than  2  metres.  The 
sub-surface  temperature  steadily  lowered  from  this  time  as 
the  colder  months  came  on,  and  the  depth  of  zero  tempera- 
ture descended  to  below  the  limit  of  the  experiments,  which 
was  only  a  little  more  than  2  meters.  The  form  of  the 
temperature  curves  in  dependence  upon  depth  showed 
clearly,  however,  that  at  very  moderate  depths  equalization 
occurred.  Late  in  March  the  lowest  temperatures  were 
reached  with  —26.3°  C.  for  the  immediate  sub-surface 
temperature,  and  —9°  C.  for  the  temperature  at  depth  of 


164        CHARACTERISTICS  OF  EXISTING  GLACIERS 


-12.0" 


-98" 


Feb 


-26.3* 


/.$• 


2.m 


2  metres.  Warm  weather 
at  the  surface  resulted  in 
a  warm  wave  which  de- 
%  scended  through  the  snow, 
following  the  colder  one, 
and  so  resulted  in  a  maxi- 
mum temperature  not 
immediately  below  the 
surface,  but  at  increasing 
distances  from  it  depend- 
ing upon  the  duration  of 
the  warmer  air  tempera- 
tures at  the  surface. 
Thus,  a  ten  day  foehn  in 
January  raised  the  tem- 
perature at  a  depth  of  2.2 
metres,  by  half  a  degree. 
It  required  over  two  days- 
for  this  rise  in  temperature 
to  proceed  to  a  depth  of  1 
meter,  and  ten  days  for  it 
to  reach  the  depth  of  2 
meters.  Similar  effects 
are  produced  with  the 
coming  of  the  more  pro- 
longed warm  weather  of 
the  summer  season  (see 
Fig.  89). 5 

When  the  surface  zone 
of  the  snow  has  reached 
the  fusing-point  of  snow, 
melting  begins  rapidly. 
Peary  has  drawn  a  graphic 
picture  of  the  effect  of  the 


DEPLETION  OF  THE  GREENLAND  ICE 


165 


warm  season  upon  the  margins  of  the  Greenland  ice.  Late 
in  the  spring  the  warmth  of  the  sun  at  midday  softens  the 
surface  first  along  the  outermost  borders  of  the  ice,  and 
this,  freezing  at  night,  forms  a  light  crust.  Gradually  this 
crust  extends  up  in  the  direction  of  the  interior,  and  as  the 
season  advances  the  surface  of  the  marginal  rim  becomes 
saturated  with  water.  This  zone  of  slush  follows  behind 
the  crust  towards  the  interior  in  a  continually  widening 
zone  as  the  summer  advances.  Within  the  outermost  zone 


FIG.   90.  —  Map  showing   the   superglacial    streams  within   the  marginal  zone  of 
the  inland-ice  of  Greenland  (after  Nordenskjold). 

the  ice  is  so  decomposed  that  pools  come  to  occupy  depres- 
sions upon  the  surface,  and  streams  cut  deep  gullies  into  the 
ice.  At  the  same  time,  the  ice  shows  a  more  dirty  appear- 
ance through  the  concentration  of  the  rock  debris  due  to  the 
melting  of  surface  layers  of  ice.  By  the  'end  of  the  season, 
pebbles,  boulders,  and  moraines  have  in  places  made  their 
appearance  on  the  surface,  and  the  streams  have  left  a  sur- 
face of  almost  impassable  roughness.6 

Differential  Surface  Melting  of  the  Ice.  —  In  his  ascent  of 
the  western  margin  of  the  ice  near  the  latitude  of  Disco  Bay, 


166        CHARACTERISTICS  OF  EXISTING  GLACIERS 

Peary  encountered  lakes  surrounded  by  morasses  of  water 
saturated  with  snow.  The  ice  within  this  zone  is  crevassed, 
and  down  the  fissures  some  of  the  surface  streams  disappear, 
at  times  in  a  large  water-fall,  and  again  in  a  "  mill  "  of  its 
own  shaping.  Baron  Nordenskjold  earlier  observed  almost 
identically  the  same  phenomena  along  the  line  of  his  route. 
The  intricate  ramifications  of  the  superglacial  rivers  and  the 
occupation  of  almost  the  entire  remaining  surface  of  the  ice 
by  shallow  ice  wells  and  basins  along  his  route  are  shown  in 


I  c-t  s'ck^r  s  be^cw 

C 

FIG.  91.  —  Diagrams  to  show  the  effects  on  differential  melting  on  the  ice  surface  : 
a,  dust  wells  ;  6,  basins  ;  c,  glacier  stars  ;  d,  bagnoires. 

Figs.  90  and  93.7  These  ice  wells  are  in  no  wise  restricted  to 
inland-ice,  but  are  found  on  mountain  glaciers  as  well,  and 
represent  but  one  of  a  series  of  allied  phenomena  dependent 
upon  differential  melting  due  to  the  presence  of  rock  frag- 
ments upon  the  ice. 

The  influence  of  heat  radiated  from  rock  particles  which  lie 
upon  the  surface  of  snow  or  ice,  has  never  been  properly 
recognized.  During  the  construction  of  the  Bergen  Railway, 
which  was  completed  across  Norway  in  December,  1909,  it 
was  necessary  each  summer  to  clear  away  great  banks  of 
snow  lying  upon  the  right  of  way,  before  the  work  of  the  sea- 


DEPLETION  OF  THE  GREENLAND  ICE 


167 


son  could  be  said  to  be  begun.  The  labors  of  an  army  of 
shovellers  which  had  at  first  made  somewhat  ineffectual  at- 
tacks upon  the  drifts,  were  later  replaced  by  the  sun,  a  layer 
of  earth  or  sand  having  been  spread  over  the  snow  surface. 
In  this  way  it  was  learned  that  drifts  which  would  otherwise 
have  been  but  little  diminished  in  size  sank  as  much  as  six 
feet  in  the  course  of  a  month. 

Ice  wells  and  allied  phenomena  due  to  differential  melting 
about  rock  particles  on  the  ice  surface  were  described  by 


=  Layer  warmed  by 

FIG.  92.  —  Fragments  of  rock  of  different  sizes  to  show  their  effect  upon  melting 

on  the  ice  surface. 

Agassiz  in  his  "  System  Glaciare."  The  particles  of  rock  if 
not  contiguous  upon  the  ice  surface  absorb  the  sun's  rays 
and  cause  excessive  melting  of  the  ice  about  and  beneath 
them.  They  thus  sink  down  into  the  ice  and  form  dust  wells 
(Fig.  91,  a).  The  thin  walls  which  separate  those  wells  which 
are  close  together,  being  now  attacked  by  the  warm  air  on 
their  sides  instead  of  on  the  top  only,  they  in  their  turn  melt 
away  to  form  a  small  basin,  which  soon  either  wholly  or  in 
part  fills  with  water  (Fig.  91,  6).  Where  in  contact  with  their 
neighbors  and  where  of  such  thickness  of  accumulation  as 
not  to  be  heated  through  by  the  sun's  rays,  these  rock  parti- 
cles behave  in  quite  a  different  manner  and  protect  the  ice 


168        CHARACTERISTICS   OF  EXISTING  GLACIERS 

beneath  them  from  the  sun  (note  margins  of  wells  and  basins 
in  Fig.  91,  a  and  6).  The  same  effect  is  brought  .about  if  the 
fragments  are  too  large,  for  the  thickness  of  surface  layer  of 
rock  which  can  be  sensibly  warmed  by  the  sun's  rays  is  quite 
independent  of  the  size  of  the  fragment.  Thus  the  familiar 
ice  tables  developed  especially  upon  mountain  glaciers  are 
formed.  Fig.  92  brings  this  out  by  showing  the  relation  of 
the  warmed  surface  layer  to  the  whole  fragment  —  (a)  in  a 
dust  well,  (6)  in  a  pebble  that  sinks  slightly  into  the  ice  until 
it  reaches  equilibrium,  (c)  in  a  slab  of  such  size  as  to  neither 
facilitate  nor  retard  surface  melting,  and  (d)  in  a  large  pro- 
tective slab  of  rock. 

The  basins  which  result  from  the  dust  wells  induce  still 
other  interesting  structures.    At  night  the  water  within  these 


FIG.  93.  —  Section  of  the  so-called  "  cryoconite  holes"  upon  the  surface  of  an  ice 
hummock  (after  Nordenskjold). 

basins  freezes  in  the  form  of  needles  which  everywhere  pro- 
ject inward  from  the  steep  walls  of  the  basin.  After  repeated 
freezings  the  basins  are  often  entirely  closed  by  these  needles 
and  thus  form  "  glacier  stars  "  (see  Fig.  91,  c).  Elongated 
basins  have  been  given  the  name  bagnoires  (see  Fig.  91,  d). 
From  studies  of  such  phenomena  resulting  from  differential 
melting  as  developed  upon  the  Great  Aletsch  Glacier,  we  have 
found  that  the  segregation  of  the  rock  debris  upon  the  bot- 
tom of  the  basins  later  protects  those  areas  after  melting  of 
the  general  surface  has  drained  them  of  their  water.  Thus 


DEPLETION  OF  THE  GREENLAND  ICE  169 

the  familiar  debris-covered  ice  cones  come  into  existence  and 
further  increase  the  irregularities  of  the  ice  surface.  The 
dust  wells  and  basins  which  were  described  by  Nordenskjold 
over  large  areas  covered  the  sides  of  steep  hummocks  in  the 
ice  as  well  as  its  more  level  surfaces  (see  Fig.  93). 

On  his  return  from  his  attack  upon  the  inland-ice  near 
Disco  Bay,  Peary  travelled  for  seven  hours  through  half- 
frozen  morasses  alternating  with  hard  blue  ice  honeycombed 
with  water  cavities.  Then  the  character  of  the  ice  com- 
pletely changed,  the  slush  and  the  water  cavities  disappeared, 
and  the  entire  surface  was  granular  snow-ice,  scored  in  every 
direction  with  furrows,  one  to  four  feet  deep,  and  two  to  ten 
feet  in  width,  with  a  little  stream  at  the  bottom  of  each.8 

Moats  Between  Rock  and  Ice  Masses.  —  Wherever  the  ice 
sends  an  outlet  down  a  valley,  the  edges  of  this  ice  shrink 
away  from  the  warmer  rocks  on  either  side,  thus  leaving 
lateral  canyons  walled  with  ice  on  the  one  hand  and  with  rock 
upon  the  other.  Down  these  canyons  are  the  courses  of 
glacial  streams.9  An  excellent  example  of  such  a  lateral 
stream  is  furnished  by  the  Benedict  glacier  (Plate  25,  A).10 

In  most  cases  where  nunataks  project  through  the  ice  sur- 
face, the  absorption  of  the  sun's  rays  by  the  rock  melts  back 
the  ice  so  as  to  leave  a  deep  trench  surrounding  the  island  and 
much  resembling  the  moat  about  an  ancient  castle.  Snow 
drifted  by  the  wind  often  bridges  or  partially  fills  the  moat. 
Upon  nunataks  forty  miles  within  the  border  of  the  ice  in 
northeast  Greenland  the  Danes  found  water  running  in  the 
ravines  and  disappearing  under  the  ice  at  the  margin  of  the 
nunatak  where  it  "  formed  the  most  fantastic  ice-grottoes, 
where  the  light  was  broken  into  all  colors  through  the  crystal 
icicles."  u 

Such  moats  have  been  mentioned  by  nearly  all  explorers 
upon  the  ice.  It  has  been  claimed  by  von  Drygalski  that 
this  phenomenon  is  characteristic  of  the  west  coast  margin 


170     .  CHARACTERISTICS  OF  EXISTING  GLACIERS 

only,  more  ample  nourishment  upon  the  eastern  coast  making 
the  snow  rise  about  the  rock  like  a  water  meniscus.  Ryder12 
and  Jensen 13  have  each  figured  such  moats  from  the  extreme 
south  of  Greenland.  By  Jensen's  party  these  moats  were 
made  use  of  for  camping-places.  Peary,  however,  has  shown 
that  the  moats  upon  the  west  coast  are  often  largely  filled 
with  snow.14  Stein  mentions  this  as  a  common  feature  after 
snow  storms,15  and  Chamberlin  16  asserts  that  wherever  the 
motion  of  the  ice  is  considerable  the  trench  does  not  appear, 
but  the  ice  impinges  forcibly  upon  the  base  of  the  nunatak. 

Englacial  and  Subglacial  Drainage  of  the  Inland-ice.  —  In 
addition  to  the  superglacial  streams  which  are  so  much  in  evi- 
dence, others  which  are  englacial  run  beneath  the  surface  of 
the  ice,  as  has  often  been  discerned  by  putting  the  ear  close  to 
the  ice  surface .  Nordensk j  old  reports  one  instance  where  water 
spouted  up  from  the  surface  mixed  with  a  good  deal  of  air  and 
spray.17  Salisbury  also  has  mentioned  a  huge  spring  upon 
the  surface  of  the  ice  in  north  Greenland  that  shot  up  to  a 
distance  of  not  less  than  ten  feet  above  the  bottom  of  the 
basin  from  which  it  issued.  Owing  to  the  fact  that  near  the 
margin  of  the  ice  its  surface  is  much  crevassed,  comparatively 
little  water  can  continue  to  the  border  in  surface  streams. 
Salisbury  mentions  an  instance  where  an  englacial  stream 
with  a  diameter  of  about  five  feet  issued  from  the  vertical  face 
which  formed  the  ice  front.  Most  of  the  water  flowing  upon 
the  surface  descended,  however,  to  the  bottom,  and  issued 
largely  below  the  surface  of  the  fluvio-glacial  materials.  It 
is,  he  says,  a  rare  exception  to  find  a  visible  stream  issuing 
from  beneath  the  ice  at  its  margin.  In  most  cases,  the  water 
undoubtedly  comes  out  in  quantities,  though  beneath  the  sur- 
face of  the  outwash  apron,  as  could  be  detected  by  the  ear.18 
Poary  has  observed  that  a  greater  abundance  of  water  issues 
from  beneath  the  ice-cap  in  extreme  northeastern  than  in 
northwestern  Greenland.19 


PLATE  25. 


A.    Lateral  glacial  stream  flowing  between  ice  and  rock,  Benedict  glacier  tongue 

(after  Peary). 


B    The  ice-dammed  lake  Argentine  in  Patagonia  (after  Sir  Martin  Con  way). 


DEPLETION   OF  THE  GREENLAND   ICE 


171 


The  Marginal  Lakes.  —  Wherever  the  ice  has  withdrawn 
from  the  rock  surface,  and  where  ice  drainage  permits  of  it, 
small  lakes  marginal  to  the  inland-ice  have  come  into  exist- 
ence. Special  interest  attaches,  however,  to  those  bodies 
of  water  which  are  impounded  by  the  ice  itself  along  its 
margin,  because  of  the  light  which  is  thrown  upon  the  ori- 
gin of  somewhat  similar  bodies  of  water  about  the  great 
continental  glaciers  of  Europe  and  North  America  during 
late  Pleistocene  times.  Attention  was  called  to  such  ice- 


FIG.  94.  —  Map  showing  the  margin  of  the  Frederikshaab  ice  apron  extending  from 
the  inland-ice  of  Greenland  and  showing  the  position  of  ice-dammed  marginal 
lakes  (after  Jensen). 

dammed  lakes  situated  upon  the  margin  of  the  Frederiks- 
haab tongue  of  the  inland-ice  by  the  Jensen,  Kornerup,  and 
Groth  expedition  of  1878.  A  map  of  this  region  was  pub- 
lished by  Jensen  (see  Fig.  94). 20  Here  the  lakes  filled  with 
water  from  the  melting  of  the  glacier  by  which  their  outlets 
are  blocked,  stand  at  different  levels.  The  Tasersuak  on  the 
south,  standing  at  a  level  of  940  feet  above  the  sea,  is  blocked 
by  ice  at  both  ends  and  is  covered  by  bergs  which  are  calved 


172        CHARACTERISTICS  OF  EXISTING   GLACIERS 

from  the  ice  cliffs.  This  lake  drains  through  a  canal  upon  the 
ice  to  a  much  smaller  lake  standing  at  a  level  of  640  feet,  and 
thence  through  a  small  river  to  the  head  of  the  Tiningerf  jord. 
To  the  northward  of  the  apron  of  ice  another  long  fjord  is 
blocked  by  a  T-shaped  extension  of  ice  into  its  central  por- 
tion. Thus  there  result  two  fresh  water  lakes  standing  at 
different  levels,  the  lower  one,  like  the  Tasersuak,  with  ice  cliffs 
at  both  ends,  and  the  other  blocked  at  one  end  only  by  the 
ice.  A  slight  retreat  of  the  inland-ice  of  this  district  would 
retire  the  T-shaped  extension  of  the  glacier,  and  the  two 
smaller  lakes  would  thus  become  united  into  one  at  the  level 
of  the  lower.  A  still  further  withdrawal  of  the  Frederiks- 
haab  glacier  tongue  would  open  an  outlet  for  this  lake  to  the 


Sea  Level. 


FIG.  95.  —  Diagram  showing  arrangement  of  shore  lines  from  marginal  lakes  to  the 
northward  of  the  Frederikshaab  ice  tongue,  if  its  front  should  retire  past  the 
outlet  of  the  lower  lake. 

sea  at  a  still  lower  level.  Souvenirs  of  these  events  would  be 
left  in  a  series  of  parallel  shore  lines  ascending  in  step-like  suc- 
cession to  the  head  of  the  fjord  (see  Fig.  95).  Suess  has  used 
this  illustration  to  explain  the  vexed  problem  of  the  seter, 
the  abandoned  shore  lines  of  Norway,  which  he  claims  have 
this  peculiarity  of  arrangement.21 

The  famous  "parallel  roads  "  of  glens  Roy,  Glaster,  and 
Spean  in  the  Scottish  highlands,  which  have  in  similar 
manner  vexed  geologists,  but  which  were  finally  given  a  satis- 
factory explanation  by  Jamieson,22  find  here  a  living  model. 
Still  later  a  nearly  identical  example  from  Pleistocene  times 
has  been  supplied  from  the  Green  Mountains  to  the  eastward 
of  Lake  Champlain.23 

About  the  Cornell  tongue  of  the  inland-ice  of  Greenland 


DEPLETION  OF  THE  GREENLAND  ICE  173 

are  many  marginal  lakes  situated  where  the  border  drainage 
has  been  blocked  by  the  glacier  itself.  These  lakes  have 
been  described  by  Tarr,  who  says: 24  — 

In  its  passage  down  the  valley,  between  the  ice  and  the  land, 
the  marginal  stream  finally  enters  the  sea.  During  its  passage  it 
now  and  then  encounters  tongues  of  ice,  and  for  a  distance  flows 
along  them,  and  finally  beneath  them,  where  the  glacier  edge  rests 
against  a  moraine,  or  the  rock  of  the  land.  Again  it  falls  over  a 
rock  ledge  as  a  cascade,  or  even  a  grand  waterfall ;  and  every  here 
and  there  it  is  dammed  to  form  a  marginal  lake.  Dozens  of  these, 
great  and  small,  were  seen  along  the  margin ;  and  they  varied  in 
size  from  tiny  pools  to  ponds  half  a  mile  in  length,  and  200  to  300 
yards  in  width. 

Since  the  water  of  the  marginal  streams  is  everywhere  milky 
with  sediment,  these  lakes  are  receiving  quantities  of  muddy  de- 
posits, and  in  them  tiny  deltas  are  being  built.  Where  the  lake 
waters  bathed  the  ice  front  little  icebergs  are  coming  off,  in  exactly 
the  same  way  as  in  the  fjord  at  the  glacier  front,  and  these  are 
bearing  out  into  the  lake  large  rock  fragments  which  are  being 
strewn  over  the  bottom  or 'on  the  shores.  Also  at  the  base  of  the 
cliffs,  as  well  as  on  some  of  the  deltas  formed  by  rapidly  flowing 
streams,  pebbles  and  boulders  are  being  mixed  with  the  clay. 

Nearly  every  lake  shows  signs  of  alteration  in  level  resulting 
from  the  change  in  outflow  either  to  some  point  beneath  the  ice, 
when  the  lake  may  be  entirely  drained,  or  to  some  lower  outlet 
for  the  lake  opened  by  a  change  in  the  ice  front,  or  by  the  down 
cutting  of  the  stream  bed  where  it  is  eating  its  way  through  a 
morainic  dam.  The  different  elevations  are  plainly  evident  from 
the  absence  of  lichens  on  the  rocks,  the  clay  clinging  to  the  rocky 
shores,  and  the  beach  terraces  along  the  old  shore  lines.  In  one 
case,  at  the  western  end  of  Mount  Schurman,  a  lake  of  this  type, 
with  a  depth  of  at  least  100  feet  has  recently  been  drained.  Where 
these  extinct  lake  beds  exist  one  sees  revealed  an  expanse  of  muddy 
bottom  with  scattered  blocks  of  rock. 

In  plate  26,  A  and  B  are  represented  after  Tarr,  in  the  one 
case,  one  of  the  marginal  lakes,  and  in  the  other,  the  forma- 
tion of  a  delta  under  the  conditions  described.  From  the 


174        CHARACTERISTICS  OF  EXISTING  GLACIERS 

Karajak  district  on  the  northern  side  of  the  Upper  Nugsuak 
Peninsula,25  von  Drygalski  has  described  in  addition  to  the 
usual  rock  basin  lakes  left  by  the  withdrawal  of  the  ice  front, 
a  true  ice-dammed  lake  which  appears  upon  his  map  as  the 
Randsee.2* 

No  one  of  the  marginal  lakes  thus  far  described  furnishes 
a  parallel  to  the  interesting  Pleistocene  glacial  lakes  of  the 
Laurentian  basin  of  North  America,  since  these  developed  for 
the  most  part  upon  a  surface  of  relatively  mild  relief,  and  the 
shores  not  formed  by  the  glacier  itself  were  generally  mo- 
raines registering  an  earlier  position  during  the  retirement  of 
the  ice  front.  Perhaps  an  existing  example  comes  nearest  to 
being  realized  in  connection  with  those  glaciers  which  descend 
the  eastern  slopes  of  the  Andes  and  enter  the  great  lakes  im- 
pounded behind  moraines  of  an  earlier  extension  of  the  same 
ice  tongues.27  In  these  cases  the  ice  fronts  of  the  glaciers  are 
cut  back  into  cliffs  from  which  are  derived  the  bergs  that 
float  upon  the  surface.  The  ice  cliff  and  some  of  the  bergs 
of  Lake  Argentine  are  shown  in  plate  25,  B.  According  to 
Moreno,  Lake  Tyndall  is  bounded  on  the  west  by  true  inland- 
ice,28  the  remnant  of  the  larger  sheet  of  Pleistocene  times. 

Ice  Dams  in  Extraglacial  Drainage. — In  north  Greenland 
outside  the  ice  front,  the  brooks  sometimes  offer  a  striking 
example  of  ice  obstructions  forming  by  irrigation.  This  is 
often  the  case  where  their  beds  are  wide  and  are  covered 
with  boulders.  The  water  generally  continues  to  run  beneath 
the  stones  for  a  great  part  of  the  winter.  Later,  however, 
its  outlets  may  freeze  up,  whereupon  the  water  rises,  inundat- 
ing the  stones  and  covering  them  with  an  ice  crust.  Through 
successive  obstruction,  overflowing,  and  freezing  of  these 
streams,  the  ice  dam  which  results  may  attain  to  such  a  thick- 
ness that  it  is  still  to  be  found  at  these  places  late  in  the 
summer  when  the  ice  and  snow  have  elsewhere  disappeared 
from  the  low  land.29  The  significance  of  such  dams  as 


PLATE  26. 


A.    Ice-dammed   lakes   on   the   margin  of   the  Cornell   tongue  of   the   inland-ice 

(after  Tarr). 


B.    Delta  in  one  of  the  marginal  lakes  to  the  Cornell  glacier  tongue  (after  Tarr). 


DEPLETION  OF  THE  GREENLAND  ICE  175 

obstructions  during  a  readvance  of  the  ice  front  may  well 
be  considerable. 

Submarine  Wells  in  Fjord  Heads.  —  Rink  states  that  the 
sea  flowing  into  the  fjord  in  front  of  the  glacier  outlet  which 
ends  below  the  water  level,  is  kept  in  almost  continual  motion 
by  eddies  not  unlike  those  which  are  seen  where  springs  issue 
from  the  bottom  of  a  shallow  lake.  Such  areas  upon  the 
surface  of  the  fjord  may  generally  be  recognized  by  the  flocks 
of  sea  birds  which  circle  above  them  and  now  and  then  dive 
for  food.30  The  existence  of  such  fresh  water  streams  as  this 
implies  may  also  be  inferred  from  the  strong  seaward  current 
that  prevails  in  the  fjords  and  which  is  so  effective  in  clearing 
them  of  bergs.  Such  a  whirlpool  of  fresh  water  or  "  submar- 
ine well  "  was  observed  by  Rink  in  the  Kvanersokfjord  (lat. 
62°  N.)  which  was  over  100  yards  in  diameter.  The  kitti- 
wakes  flocked  over  the  spot,  and  the  water  was  muddy, 
although  no  brooks  were  observed  along  neighboring  shores. 
This  well  Rink  believed,  from  reports  furnished  by  the  na- 
tives, to  be  much  smaller  than  the  similar  ones  in  some  other 
fjords. 

According  to  Rink 31  the  lateral  lake  which  borders  the  in- 
land-ice of  Greenland  in  one  of  the  branches  of  the  Godthaab- 
fjord-Kangersunek  suffered  changes  of  level  just  when  the 
submarine  wells  before  the  ice  cliff  in  the  fjord  showed  marked 
changes  in  volume.  Thus,  whenever  the  water  of  the  lake 
suddenly  subsides,  the  submarine  wells  from  the  bottom  of 
the  fjord  burst  out  with  violence.  On  the  other  hand,  when 
the  water  in  the  lake  is  rising,  the  wells  are  relatively  quiet. 
These  sudden  discharges  of  the  water  from  lateral  lakes, 
save  only  that  their  outlet  is  submarine,  seem  thus  to  be 
in  every  way  analogous  to  the  spasmodic  discharges  of  the 
famous  Marjelensee  upon  the  margin  of  the  Great  Aletsch 
Glacier  in  Switzerland.  When,  as  occasionally  happens, 
this  lake  empties  through  the  opening  of  a  passage  beneath 


176        CHARACTERISTICS  OF  EXISTING   GLACIERS 

the  glacier,  the  villages  which  are  situated  miles  below  in  the 
valley  are  suddenly  inundated  with  water. 

REFERENCES 

1  R.  S.  Tarr,  "Difference  in  the  Climate  of  the  Greenland  and  Ameri- 
can Sides  of  Davis'  and  Baffin's  Bay,"  Am.  Jour.  Sci.,  vol.  3,  1897,  pp. 
315-320. 

2  An  interesting  practical  illustration  of  the  effectiveness  of  such  debris 
as  a  melting  agent  has  been  furnished  during  the  construction  of   the 
Bergen  Railway  in  Norway,  which  was  completed  in  December,  1909.     A 
prime  factor  in  the  work  was  a  means  of  clearing  the  snow  so  as  to  pro- 
long the  summer  season.     For  this  purpose  covering  the  snow  surface 
with  fine  dirt  proved  more  effective  than  a  corps  of  shovellers,  the  sun  in 
this  case  performing  the  work. 

3  Mohn  und  Nansen,  1.  c.,  p.  90. 

4  Trolle,  1.  c.,  p.  66. 

6E.  von  Drygalski,  "Gronland-Expedition,"  L  c.,  pp.  460-466. 

6  Peary,  Geogr.  Jour.,  L  c.,  p.  218.     See  also  Nordenskjold,  "  Gronland" 
(German  ed.),  pp.  125-138. 

7  A.  E.  Nordenskjold,  "Gronland,"  pp.  197-204,  map  3. 

8  Jour.  Am.  Geogr.  Soc.,  I.  c.,  p.  282. 

9  Peary,  Jour.  Am.  Geogr.  Soc.,  I.  c.,  p.  286. 

10  R.  E.  Peary,  "North  Polar  Exploration,  Field  Work  of  the  Peary 
Arctic  Club,"  1898-02,  Ann.  Rept.  Board  of  Regents  Smith.  Inst.  for  1903, 
1904,  p.  517.     Cf .  also  the  almost  identical  (if  smaller  scale)  effects  for  Ice- 
landic and  Norwegian  ice-caps.     This  volume,  ante,  p.  101. 

11  Trolle,  Scot.  Geogr.  Mag.,  vol.  25,  1909,  pp.  65-66. 

12  C.  H.  Ryder,  "  Undersogelse  af  Gronlands  Vestkyst  fra  72°  till  74°  35', 
1886-1887,"  Med.  om  Gronland,  Heft  8,  pi.  xiii. 

13  J.  A.  D.  Jensen,  " Expeditionen  till  Syd.  Gronland,"  1878,  ibid.,  Heft 

1,  pi.  iv. 

14  Peary,  Geogr.  Jour.,  I.e.,  p.  217. 

15  Stein,  I.  c. 

16  Chamberlin,  Jour.  Geol,  vol.  3,  1895,  pp.  567-568. 

17  A.  E.  Nordenskjold,  "Gronland,"  p.  137. 

18  Salisbury,  L  c.,  pp.  806-7. 

19  Peary,  Geogr.  Jour.,  I.  c.,  p.  224. 

20  Meddelelser  om  Gronland,  Heft  1.    This  map  has  been  many  times 
copied,  best  by  Nordenskjold  in  his  "Gronland"  on  p.  161. 

21  Beside  the  Jakobshavn  ice  tongue,  there  is  another  lake  confined  in 
like  manner  to  the  Tasersuak.     (Ed.  Suess,  "The  Face  of  the  Earth,"  vol. 

2,  pp.  346-363.) 

22  Thomas  T.  Jamieson,  On  the  parallel  roads  of  Glen  Roy  and  their 
place  in  the  history  of  the  glacial  period.     Quart.  Jour.  Geol.  Soc.,  vol.  19, 
1863,  pp.  235-259. 

23  H.  E.  Merwin,  "  Some  late  Wisconsin  and  Post- Wisconsin  Shore-lines 


DEPLETION  OF  THE  GREENLAND   ICE  177 

of  Northwestern  Vermont,"  Rept.  Vermont  State  Geologist,  1907-08,  pp. 
113-137,  pi.  21. 

24  R.  S.  Tarr,  "The  Margin  of  the  Cornell  Glacier,"  Am.  GeoL,  vol.  20, 
1897,  pp.  150-151. 

25 ««  Tne  Cornell  tongue  is  situated  upon  the  southern  side  of  the  same 
Peninsula." 

26  E.  von  Drygalski,  "Gronland-Expedition,"  vol.  1,  pp.  61-63,  map  2. 

27  Francisco  P.  Moreno,  "Explorations  in  Patagonia,"  Geogr.  Jour.,  vol. 
14,  1899,  pp.  253-256.     Also  Hans  Steffen,  "The  Patagonian  Cordillera 
and  its  Main  Rivers  between  41°  and  48°  South  latitude,"  ibid.,  vol.  16, 
1900,  pp.  203-206.     Also  Sir  Martin  Conway,  "Aconcagua  and  Tierra  del 
Fuego,"  London,  1902,  pp.  134-135. 

28  See  also  P.  D.  Quensel,  "On  the  Influence  of  the  Ice  Age  on  the  Con- 
tinental watershed  of  Patagonia,"  Bull.  GeoL  Inst.  Upsala,  vol.  9,  1910, 
pp.  60-92,  2  maps.     See  also,  R.  Hauthal,  "Der  Bismarck-Gletscher,  ein 
vorriickender  Gletscher  in  der  patagonischen  Cordillere,"  Zeit.  f.  Gletscherk., 
vol.  5,  1910,  pp.  133-143,  figs.  1-7. 

29  Henry  Rink,  "Danish  Greenland,  Its  People  and  its  Products,"  Lon- 
don, 1877,  p.  366. 

30  Rink,  /.  c.,  pp.  50,  360-363. 

31  Rink,  I.  c. 


CHAPTER  XI 

DISCHARGE  OF  BERGS  FROM  THE  ICE  FRONT 

The  Ice  Cliff  at  Fjord  Heads.  —  Wherever  the  inland-ice 
reaches  the  sea  in  the  fjord  heads,  and  where  it  comes  directly 
to  the  sea  in  broad  fronts,  as  it  does  near  Melville  Bay,  at 
Jokull  Bay,  and  on  the  north  side  of  Northeast  Foreland,  it  is 
here  attacked  directly  by  the  waves  and  is  further  under- 
mined through  melting  in  the  water.  The  crevassing  of  its- 
surface  over  the  generally  steep  descents  to  the  fjords,  in  a 
large  measure  facilitates  the  attack  of  the  water  upon  the 
ice  by  offering  planes  of  weakness  similar  to  the  joint  planes 
in  rock  cliffs  attacked  by  the  sea  on  headlands.  The  fjords, 
though  often  quite  narrow,  are  generally  of  great  depth,  so 
that,  although  the  ice  cliff  often  rises  to  a  height  of  several 
hundred  feet,  its  base  probably  rests  upon  the  bottom  of 
the  fjord.  To  this  a  possible  exception  has  been  noted  for 
the  great  Karajak  glacier,  of  which  a  relatively  flat  front  sec- 
tion may  be  assumed  to  be  the  surface  of  a  floating  portion 
(see  Fig.  96). 1  To  this  interesting  example  of  a  floating  gla- 
cier outlet  in  connection  with  the  inland-ice  of  the  northern 
hemisphere,  we  may  recall  the  probably  floating  front  of  the 
Turner  glacier,  a  dendritic  glacier  of  the  tide-water  type  in 
Alaska.  For  its  type  this  example  is  apparently  unique.2 

Manner  of  Birth  of  Bergs  from  Studies  in  Alaska.  —  The 
birth  of  bergs  from  the  parent  glacier  has  been  often  described 

178 


DISCHARGE  OF  BERGS  FROM  THE  ICE  FRONT     179 

by  travellers,  and  the  superlatives  of  the  language  have  been 
drawn  upon  to  express  the  grandeur  and  beauty  of  the  ob- 
served phenomena.  Simple  as  the  process  may  appear  to  the 
casual  tourist  who  makes  the  usual  summer  excursion  to 
Alaska,  it  is  not  free  from  serious  difficulties,  and  has  given 

inn 


Kilometers. 


FIG.  96.  —  Sections  from  the  inland-ice  through  the  Great  and  Little  Karajak  out- 
lets to  the  Karajak  fjord  (after  Von  Drygalski). 

rise  to  conflicting  views  among  specialists.  The  water  in 
front  of  the  ice  cliff  is  generally  so  muddy,  and  the  danger  of 
approaching  the  ice  front  so  great,  that  exact  data  are  neces- 
sarily difficult  to  obtain.  The  smaller  bergs  composed  of 
white  ice,  which  are  seen  to  fall  into  the  water  from  the  cliffs 
at  almost  all  hours,  offer  no  difficulties  of  explanation,  but 
they  are  likewise  without  great  significance  as  concerns  the 
manner  of  formation  of  those  great  floating  masses  of  ice 
which  are  carried  far  to  sea  and  scattered  over  wide  areas  of 
the  ocean  before  their  final  dissolution  in  the  warmer  south- 
ern waters.  It  is,  however,  interesting  to  find  that  the 
overriding  of  the  lower  layers  of  the  ice  by  the  upper 
greatly  facilitates  the  separation  of  this  type  of  small  ice- 
berg. Engell,  who  has  studied  the  Greenland  icebergs, 
shows  that  while  this  is  true  of  icebergs  formed  in  fjord 
heads,  it  plays  no  part  with  those  calved  from  the  sides  of 
glacier  outlets  where  ice  dammed  lakes  (see  below)  make 
iceberg  formation  possible.3 
The  larger  bergs,  instead  of  falling  from  the  cliffs,  suddenly 


180         CHARACTERISTICS  OF  EXISTING  GLACIERS 

rise  out  of  the  water  as  ice-islands,  often  several  hundred  feet 
in  front  of  the  ice  cliff.  A  wholly  satisfactory  solution  of  the 
problem  of  their  birth  involves  a  nice  quantitative  adjust- 
ment of  several  factors,  all  of  which  are  undoubtedly  more  or 
less  concerned.  On  the  one  hand,  there  is  wave  action  which 
is  effective  especially  near  the  water  level  and  has  a  direct 
range  of  action  extending  from  a  distance  below  the  surface 
equal  to  the  length  of  a  storm  wave  in  the  fjord,  and  to  a 
height  above  the  quiet  level  equal  to  the  height  of  the  wave's 
dash.  If  there  were  no  melting  in  the  water,  and  if  the  lower 
layers  of  the  glacier  moved  forward  as  rapidly  as  the  upper, 
the  tendency  would  undoubtedly  be  to  develop  an  erosion 
profile  in  every  way  like  that  of  a  rock-cut  terrace  upon  the 
sea  shore.  With  emphasis  upon  this  element  in  the  problem 
Russell  has  assumed  that  the  ice  cliff  in  the  fjord  is  prolonged 
outward  beneath  the  water  as  an  ice  foot  which  thins  gradu- 
ally toward  the  toe.  Upon  this  hypothesis  the  bergs  which 
rise  from  the  water  are  born  from  the  foot  where  the  increas- 
ing buoyancy  of  the  outer  portion  overcomes  the  cohesive 
strength  of  the  material  at  the  surface  where  rupture  occurs. 
This  view  accounts  particularly  well  for  those  bergs  which 
rise  from  the  water  far  in  advance  of  the  cliff  (see  Fig.  97). 4 


FIG.  97.  —  Origin  of  bergs  as  a  result  especially  of  wave  erosion  (after  Russell). 

Laying  stress  rather  upon  melting  in  the  water  and  upon 
the  rapid  forward  movement  of  the  upper  layers  of  ice  near 
the  glacier  margin,  Reid  has  arrived  at  a  wholly  different 
conclusion  concerning  the  origin  of  larger  bergs:5  — 


DISCHARGE  OF  BERGS   FROM  THE  ICE  FRONT     181 


The  more  rapid  motion  of  the  upper  part  would  result  in  its 
projection  beyond  the  lower  part,  and  this  would  become  greater 
and  greater  until  its  weight  was  sufficient  in  itself  to  break  it  off. 
The  extent  of  the  projection  before  a  break  would  occur,  depends 
evidently  upon  the  strength  of  the  ice.  .  .  .  That  the  ice  for 
several  hundred  feet  below  the  surface  does  not  in  general  project 
farther  than  that  above  is  evident  from  the  fact  that  I  have  fre- 
quently seen  large  masses,  extending  to  the  very  top  of  the  ice 
front,  shear  off  and  sink  vertically  into  the  water,  disappear  for 
some  seconds,  and  then  rise  again  almost  to  their  original  height 
before  turning  over.  If  there  were  any  projection  within  300  feet 
of  the  surface,  this  mass  would  have  struck  it  and  been  overturned 
so  that  it  could  not  have  arisen  vertically  out  of  the  water. 

Reid  thinks  there  are  three  ways  in  which  bergs  come  into 
existence  at  the  end  of  a  glacier :  - 

(a)  A  piece  may  break  off  and  fall  over  —  this  is  the  usual 
way  with  small  pinnacles ;  (6)  a  piece  may  shear  off  and  sink  into 
the  water  —  this  is  the  usual  way  with  the  larger  masses ;  or,  again, 
(c)  ice  may  become  detached  under  water  and  rise  to  the  surface. 

The  supposed  successive  forms  of  the  ice  front,  according 
to  Reid,  are  shown  in  Fig.  98. 

It  is  easy  to  see  that  Russell's  and  Reid's  views  might 
each  apply  in 
special  cases 
dependent:  (a) 
upon  the  nar- 
rowness or  the 
sinuosities  of 
the  fjord, 
which  would 

,  .  ,        FIG.  98.  —  Supposed  successive  forms  of  a  tide-water  glacier 

determine    the  front  (after  Reid)> 

reach     of     the 

waves;  (b)  upon  the  steepness  of  the  slope  back  of  the  ice 

cliff,  which  would  regulate  the  different  velocities  of  surface 


182         CHARACTERISTICS  OF  EXISTING  GLACIERS 


and  bottom  layers  of  ice,  and  determine  the  measure  of 
crevassing;  (c)  upon  the  irregularities  in  the  floor  of  the  ice 
tongue,  which  would  largely  fix  the  amount  of  shearing  and 
overthrusting;  (d)  upon  the  presence  or  absence  of  warm 
ocean  currents,  which  would  regulate  the  rate  of  melting  of 
the  ice  by  the  fjord  water;  and  (e)  upon  the  freezing  of  the 
water  surface,6  which  must  put  a  bar  upon  the  action  of  the 
waves  during  the  colder  period. 

Studies  of  Bergs  Born  of  the  Inland-ice  of  Greenland.  — 
Though  ice  bergs  are  discharged  from  the  inland-ice  through- 
out practically  the  entire  extent  of  the  coast  line  of  Green- 
land wherever  inland-ice  reaches  the  sea,  yet  the  great 
bergs  which  push  out  into  the  broad  Altantic  arise  either 


FIG.  99.  —  A  large  berg  floating  in  Melville  Bay  and  surrounded  by  sea-ice. 

on  the  west  coast  between  Disco  Bay  and  Smith  Sound,  or 
on  the  east  coast  south  of  the  parallel  of  68°.  To  the  north 
of  this  latitude  the  bergs  are  firmly  held  in  the  heavy  pack- 
ice,  while  the  bergs  of  southwest  Greenland  form  for  the  most 
part  in  such  narrow  fjords  that  they  are  too  small  to  travel 
far  before  their  final  dissolution. 


DISCHARGE  OF  BERGS  FROM  THE  ICE  FRONT     183 

The  size  of  the  Greenland  ice  bergs  has  probably  been  much 
1  overestimated.  Of  87  measurements  made  by  von  Drygal- 
ski  on  the  large  bergs  calved  in  the  Great  Karajak  fjord,  the 
highest  reached  137  metres  above  the  water,  or  about  445 
feet.  This  mass  of  ice  was,  however,  against  the  glacier 
front,  and  probably  rested  on  the  bottom.  None  of  the  others 
measured  were  much  above  100  metres  high  or  about  325 
feet.7  The  berg  shown  in  Fig.  99,  photographed  by  an 
earlier  explorer  in  Melville  Bay,  measured  250  feet  in  height. 

During  fourteen  months  spent  in  the  immediate  vicinity 
of  the  steep  front  of  the  Great  Karajak  ice  tongue,  von 
Drygalski  carried  out  extensive  studies  upon  the  calving 
of  bergs,  and  has  distinguished  three  classes.  Those  of  the 
third  class  form  almost  constantly,  and  consist  of  larger  or 
smaller  fragments  which  separate  along  the  crevasses  and 
fall  into  the  sea.  Only  twice  were  calvings  of  the  second 
class  observed,  namely,  in  late  October  and  in  early  Novem- 
ber. Of  one  of  these  von  Drygalski  says :  — 

I  heard  a  thundering  noise,  but  at  first  neither  I  nor  the  Green- 
landers  who  were  with  me  saw  anything.  Suddenly  a  great  dis- 
tance away  from  the  margin  of  the  glacier,  an  iceberg  emerged  from 
the  sea,  rose  out  of  the  water,  though  not  to  the  height  of  the  cliff, 
and  then  moved  away  accompanied  by  a  continuous  loud  tumult 
and  by  a  rise  in  the  level  of  the  water,  through  the  agency  of  which 
it  moved  away  from  the  cliff  quite  rapidly.  It  did  not  come  from 
the  cliff,  but  certainly  emerged  from  below.  The  Greenlanders, 
whom  I  afterwards  questioned  about  it,  gave  me  the  same  impres- 
sion. .  .  .  The  margin  of  the  glacier  was  unchanged. 

Here  it  was  noticed  that  the  berg  was  long,  though  not  as 
high  as  the  ice  cliff  which  terminated  the  glacier.  It  is  the 
opinion  of  von  Drygalski  that  bergs  of  this  class  come  from 
the  lowest  layers  of  the  glacier.  Because  of  the  sea-ice 
which  in  winter  forms  in  front  of  the  glacier,  the  ice  cliff 
is  at  that  time  not  cut  away  so  fast,  and  it  was,  in  fact, 


184         CHARACTERISTICS  OF  EXISTING  GLACIERS 

observed  in  the  winter  farther  out  than  during  the  summer. 
This  explanation  in  the  main  is  in  agreement  with  that  of 
Russell. 

Bergs  of  von  Drygalski's  first  class,  which  are  the  most 
massive  of  all,  separate  from  the  entire  thickness  of  the  ice 
front.  Two  such  bergs  were  observed  in  process  of  calving 
by  von  Drygalski  and  other  members  of  his  party.  The 
same  loud  sound  which  had  been  heard  at  the  birth  of  bergs 
of  the  second  class  accompanied  the  birth  of  those  in  the  first 
class,  but  the  movement  of  separation  from  the  glacier  was 
visible  at  the  same  instant.  A  portion  of  the  cliff  front  was 
seen  to  separate  from  the  cliff,  being  thereby  thrown  some- 
what out  of  equilibrium  and  started  in  a  pendular  vibration 
which  produced  great  waves  in  the  fjord  and  increased 
slightly  its  distance  from  the  newly  formed  ice  cliff.  It 
was  here  observed  that  the  main  pinnacle  of  the  berg  slightly 
exceeded  in  height  the  highest  pinnacles  of  the  new  glacier 
rim.  This,  it  will  be  remembered,  is  in  contrast  with  the 
bergs  of  the  second  class  which  did  not  reach  to  the  height 
of  the  cliff.  Bergs  of  the  first  class  usually  regain  their 
equilibrium  after  rhythmic  oscillations,  and  float  away  in  an 
upright  position.  The  bergs  of  the  second  class  often  turn 
over,  displaying  the  beautiful  blue  color  of  the  lower  layers. 
Studies  confirmatory  of  those  of  von  Drygalski  have  been 
recently  made  by  Engell,8  and  Salisbury's  two  types  of 
Greenland  icebergs  seem  to  correspond  with  von  Drygalski's 
bergs  of  the  first  and  second  classes.9 

The  water  waves  which  are  sent  out  to  the  shores  at  the 
birth  of  a  great  iceberg  extend  50  kilometres  or  more  within 
the  fjord,  driving  the  smaller  floating  bergs  together  and 
thus  assisting  in  their  fragmentation  and  consequent  dis- 
solution. The  calving  of  bergs  of  the  first  class  von  Dry- 
galski believes  occurs  where  the  depth  of  the  fjord  has  so  far 
increased  that  the  ice  begins  to  leave  the  bottom  and  assume 


DISCHARGE  OF  BERGS  FROM  THE  ICE  FRONT       185 

a  swimming  attitude.     The  buoyancy  of  the  water  is,  he 
believes,  thus  the  true  cause  of  the  separation  of  the  bergs. 

Depths  which  are  four  to  five  times  as  great  as  the  thickness 
of  the  inland-ice  above  the  sea  level,  are  not  measured  in  Green- 
land in  front  of  attached  ice  masses,  because  the  latter  become 
in  that  case  broken  up  into  ice  bergs.10 

This  view  gains  strength  from  Salisbury's  studies  of  the 
glaciers  ending  in  Melville  Bay  and  apparently  floated  for 
a  very  short  distance  back  from  their  fronts  and  generally 
in  the  middle  only.11 

REFERENCES 

1  E.  von  Drygalski,  "Gronland-Expedition,"  vol.  1,  pi.  43.     See  also 
R.  D.  Salisbury,  "The  Greenland  Expedition  of  1895,"  Jour.  Geol,  vol.  3, 
1895,  p.  885. 

2  R.  S.  Tarr  and  B.  S.  Butler,  "The  Yakutat  Bay  Region,  Alaska, 
physiography  and  Glacial  Geology,"  Prof.  Pap.  No.  64,  U.  S.  Geol.  Sur., 
1909,  pp.  39-40,  pi.  10-a. 

3  M.  C.  Engell,  "  Ueber  die  Entstehung  der  Eisberge,"  Zeit.  f.  Gletscherk., 
vol.  5,  1910,  pp.  122-132. 

4 1.  C.  Russell,  "An  Expedition  to  Mt.  St.  Elias,  Alaska,"  Nat.  Geogr. 
Mag.,  vol.  3,  1891,  pp.  101-102,  fig.  1. 

5H.  F.  Reid,  "Studies  of  Muir  Glacier,  Alaska,"  ibid.,  vol.  4,  1892, 
pp.  47-48. 

6  R.  S.  Tarr,  "The  Arctic  Ice  as  a  Geological  Agent,"  Am.  Jour.  Sci., 
vol.  3,  1897,  p.  224. 

7  E.  von  Drygalski,  "Gronland-Expedition,"  etc.,  I.  c.,  pp.  367-404. 

8  "Ueber  die  Entstehung  der  Eisberge,"  Zeit.  f.  Gletscherk.,  vol.  6,  1910, 
pp.  122-132. 

9  Jour.  Geol.,  vol.  3,  pp.  892-897. 

10  E.  von  Drygalski,  I.  c.,  p.  404. 

11  Salisbury,  Jour.  Geol,  vol.  3,  1895,  pp.  885-886. 


PART  III 

ANTARCTIC  GLACIERS 

CHAPTER  XII 
THE  ANTARCTIC   CONTINENT  AND  ITS   SEA-ICE  GIRDLE 

General  Uniformity  of  Conditions  in  Contrast  with  the 
North  Polar  Region.  —  The  essentially  reciprocal  physio- 
graphical  developments  about  the  earth's  two  polar  regions 
are  responsible  for  a  striking  contrast  in  their  physical, 
and  especially  in  their  glacial  conditions.  In  the  north  a 
deep  polar  sea  is  largely  encircled  by  a  rim  of  land  masses, 
interrupted,  however,  in  one  rather  broad  area  by  the  north- 
ern Atlantic  ocean.  Nearly  opposite  this  interruption  the 
Pacific  pushes  a  great  bay  so  far  to  the  northward  as  just 
to  pierce  the  land  girdle.  The  ridge  of  the  Aleutian  arc 
farther  to  the  south  imposes  a  bar  to  the  movement  of  ocean 
currents,  and  makes  the  break  at  this  point  a  less  important 
one  than  it  would  at  first  appear. 

The  widely  different  specific  heats  of  land  and  water, 
the  irregularities  of  the  land  surfaces,  and  especially  the 
large  transfer  of  heat  through  the  medium  of  northwardly 
and  southwardly  directed  ocean  currents,  together  bring 
about  a  great  diversity  of  climatic  conditions  within  the 
northern  polar  regions.  Along  the  same  parallel  of  latitude 

186 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE     187 

the  widest  differences  of  temperature  and  precipitation  are 
to  be  encountered. 

Within  the  south  polar  region,  on  the  contrary,  the  great 
continental  plateau,  centred  as  it  is  so  nearly  over  the  pole 
and  having  its  borders  for  long  distances  so  nearly  in  corre- 
spondence with  the  Antarctic  Circle,  the  surrounding  ocean 
permits  of  a  relatively  free  circulation  of  oceanic  waters 
and  of  air  currents.  The  result  is  a  greater  uniformity  and 
a  symmetry  in  distribution  of  the  principal  climatic  constants 
with  regard  to  the  south  pole  as  a  centre.  Here  the  iso- 
therms more  nearly  follow  the  parallels  of  latitude,  and,  there 
being  a  much  smaller  transfer  of  heat  by  ocean  currents  from 
tropical  regions,  the  climate  is  far  more  severe  than  within 
the  Arctic  regions.  For  this  reason  the  surface  of  the  sea 
freezes  in  considerably  lower  latitudes,  so  that  the  Antarctic 
continent  is  encircled  by  a  broad  zone  of  pack  ice  which  offers 
the  most  serious  bar  in  the  way  of  those  who  would  explore 
it. 

The  uniformity  of  climatic  conditions  within  the  Antarctic 
we  express  when  we  say  that  its  climate  is  oceanic.  To 
fully  understand  the  severity  of  this  climate  it  is  necessary 
to  emphasize  a  vital  difference  between  the  glaciation  of 
southern  and  of  northern  polar  regions.  Throughout  the 
Arctic  regions,  with  a  single  noteworthy  exception  of  the 
Franz  Josef  archipelago,  the  snow-ice  masses  are  all  smaller 
than  the  land  areas  upon  which  they  lie.1  Within  the  Ant- 
arctic, on  the  contrary,  the  reverse  is  the  case,  and  the 
snow-ice  masses  quite  generally  cover  all  the  land  surface  and 
push  out  also  upon  the  sea.  Barring  the  peninsula  of  West 
Antarctica,  which  sends  a  narrow  tongue  northward  two 
degrees  or  more  beyond  the  Antarctic  Circle,  land  has  been 
seen  exposed  only  in  the  high  Admiralty  and  Royal  Society 
ranges  in  Victoria  Land,  and  in  a  few  isolated  volcanic  peaks, 
such  as  Erebus  and  Terror  on  the  Ross  Sea,  and  the  Gauss- 


188         CHARACTERISTICS  OF  EXISTING  GLACIERS 

berg  of  Kaiser  Wilhelm  II  Land.  Elsewhere  the  white  snow 
surface,  variously  moulded  near  its  margin,  is  all  that  meets 
the  eye  at  the  border  of  the  continent. 

An  oceanic  climate  is  possessed  by  bodies  of  land  which 
are  surrounded  by  the  sea  and  are  so  small  that  climatic 
conditions  are  dominated  by  the  sea  rather  than  by  the  land. 
Yet  however  small  the  land  surface  may  be,  since  it  is  ex- 
posed to  the  sun's  rays,  it  is  warmed  and  cooled  more  rapidly 
than  is  the  sea,  and  in  consequence  exerts  a  counteracting 
influence  upon  the  climate  in  the  direction  of  a  greater 
changeability.  Within  the  Antarctic,  however,  where  the 
surface  is  almost  entirely  snow-covered,  the  earth  is  shielded 
from  solar  radiation,  and  no  such  influence  is  exerted.  This 
is  an  important  cause  of  the  difference  in  climate  between 
the  Arctic  and  Antarctic  regions. 

Antarctic  Temperatures.  —  Nowhere  is  the  uniformity  of 
conditions  within  the  Antarctic  region  more  strikingly 
exemplified  than  in  the  temperatures  which  prevail  and  in 
the  small  range  which  separates  the  winter  from  the  summer 
temperatures.  Thus  we  find  on  the  margin  of  the  continent 
at  or  near  the  level  of  the  sea  and  in  latitudes  near  the 
Antarctic  Circle  an  average  summer  2  temperature  which  is 
colder  than  Nansen  encountered  in  the  Arctic  ice  pack 
within  five  degrees  of  the  North  Pole.  Both  the  average 
and  the  extreme  winter 3  temperatures  are  on  the  other 
hand  as  surprising  by  reason  of  their  moderate  values. 
As  illustrating  the  oceanic  climate  of  Antarctica,  we  have 
only  to  state  that  the  extremes  of  cold  encountered  in  the 
Antarctic  regions  are  equalled  or  exceeded  by  the  tempera- 
tures registered  at  stations  south  of  the  50th  parallel  in 
North  America.  The  recent  Antarctic  expeditions  have  at 
last  supplied  us  with  reliable  data  at  several  widely  separated 
points  and  for  periods  of  a  year  or  more.  These  data  we 
have  collected  and  set  forth  in  the  following  table:  — 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE      189 


ANTARCTIC   TEMPERATURES   IN   FAHRENHEIT    DEGREES 


« 

rf 

t| 

a. 

Station 

*o 
o 

1 

£jj 

<D^f 

§ 

1 

Authority 

3    O 

•^  § 

c3  S     " 

^    Q)       " 

"3 

a  & 

i-^l  a2 

jT-s 

i-l  02 

||| 

III 

II 

II 

Snow     Hill     Island, 

West  Antarctica    . 

64°3(X 

57°  W. 

28.13 

-4 

10.76 

-42.3 

O.  Nordenskiold  * 

"Gauss"   in  the  ice 

pack   50   miles  off 

Kaiser  Wilhelm  II 

Land  

66° 

90°  E. 

-29.5 

v.  Drygalski  s 

"Belgica"  in  the  ice- 

pack off  West  Ant- 

arctica    .... 

70-71°  36' 

85-103°  W. 

29.3 

1.8 

9.6 

-45.6 

Arctowski  8 

Cape  Adare,  Victoria 

Land 

71  \/Q 

170°  E. 

30.4 

-11.3 

7.05 

-43.1 

Bernacchi  7 

Cape  Armitage,  Vic- 

toria Land   . 

778/4° 

167°  E. 

-15.15 

-21 

Shackleton  8 

Cape  Armitage,  Vic- 

toria Land   . 

77%° 

167°  E. 

-13.17 

-17 

Shackleton  8 

To  the  S.E.  of  White 

Island  on  ice  bar- 

rier near  Cape  Ar- 

mitage    .... 

-67. 

Scott  • 

(in  September) 

Thus  we  see  that  the  average  summer  temperature  upon 
the  borders  of  the  Antarctic  continent  is  from  two  to  four 
degrees  below  the  freezing-point  of  water,  or  about  the  same 
as  the  winter  temperature  of  Southern  Scandinavia.  Pass- 
ing northward  from  the  Antarctic  Circle  and  beyond  the 
margins  of  the  continent,  the  rise  in  temperature  is  rapid. 
Thus  Bruce 's  temperature  record,  taken  in  the  Weddell  Sea, 
gave  7°  F.  as  the  lowest  temperature  reached,  while  the  aver- 
age summer  temperature  was  near  31.4°  F.  and  the  average 
winter  temperature  13.7°  F.10  In  the  South  Orkney  Islands, 
only  3j°  farther  north  than  the  Snow  Hill  station  of  West 
Antarctica,  the  average  winter  temperature  is  higher  by 
14°  F.11 

The  above  described  Antarctic  temperatures  measured 


190         CHARACTERISTICS  OF  EXISTING  GLACIERS 

near  sea  level  and  on  the  margin  of  the  continent  are,  how- 
ever, quite  different  from  those  which  are  encountered  upon 
the  high  ice  plateau.  Data  from  these  levels  are  naturally 
only  available  for  brief  periods  during  the  summer  season. 
On  his  trip  westward  from  Cape  Armitage  over  the  snow 
plateau,  Scott  found  that  for  fifty  days  the  temperature 
fell  almost  nightly  to  —  40°  F.  and  seldom  rose  during  the 
day  above  —  25°  F.12  Shackleton's  southern  party  even  in 
the  height  of  summer  nowhere  upon  the  plateau  encountered 
a  temperature  above  0°  F.,  and  temperatures  between— 35° 
and  —  40°  F.  were  often  registered.13 

Geographical  Results  of  Exploration.  --The  wide  zone  of 
sea-ice  which  surrounds  the  Antarctic  continent  has  been 
an  effectual  barrier  to  navigation  of  Antarctic  waters.  If 
to  this  we  add  the  remoteness  of  the  region  from  centres  of 
civilization,  and  the  lack  of  any  lively  commercial  interest, 
such  as  the  supposed  northwest  and  northeast  passages 
to  the  orient  in  the  northern  hemisphere,  the  tardiness  of 
exploration  in  the  south  polar  regions  finds  a  sufficient 
explanation.  The  first  important  voyage  of  discovery 
in  that  region,  that  of  Captain  James  Cook  in  the  years 
1770  to  1774,  was  undertaken  to  solve  the  problem  of  the 
supposed  southern  continent,  the  Terra  Australis  Incognita. 
Cook  largely  circumnavigated  the  globe  in  the  latitude  of 
50°  south  or  more,  and  for  a  distance  of  115°  of  longitude  kept 
south  of  60°  latitude.  Three  times  he  crossed  the  Antarctic 
Circle,  and  at  one  point  attained  the  high  latitude  of  71°  10', 
but  without  discovering  the  supposed  continent.14 

It  was  the  importance  of  the  sealing  industry  in  the  South 
seas  which  some  sixty  years  after  Cook's  voyages  furnished 
the  impetus  to  the  second  great  period  of  Antarctic  dis- 
covery, that  of  1838-1841.  Three  expensive  expeditions 
fitted  out  in  the  United  States,  France,  and  England  were 
commanded  by  Wilkes,15  D'Urville,16  and  Ross17  respectively. 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE     191 

It  is  the  best  commentary  upon  the  difficulties  of  South 
Polar  exploration  that  while  all  these  expeditions  discovered 
the  Antarctic  continent,  no  one  of  them  succeeded  in  effect- 
ing a  landing.  With  the  revival  of  interest  in  Antarctica 
which  came  after  another  sixty  years  had  elapsed,  during 
which  time  strong  steam  vessels  had  replaced  the  earlier 
sailing  ships,  Borchgrevink  in  1898  wintered  at  Cape 
Adare  in  Victoria  Land,  and  could  claim  that  he  was  the  first 
to  set  foot  upon  the  Antarctic  continent.18 

The  recent  period  of  Antarctic  exploration  began,  however, 
with  the  "  Belgica  "  expedition  of  1897-1899,  which  was 
assisted  by  the  Belgian  government  and  was  commanded 
by  Lieutenant  Adrian  de  Gerlache,19  though  it  was  soon 
followed  in  1898-1900  by  the  British  Antarctic  expedition 
under  Borchgrevink.  These  two  expeditions  greatly  stim- 
ulated an  interest  in  South  Polar  exploration,  and  in  1902 
three  national  expeditions  wintered  in  the  Antarctic  —  an 
English  under  the  command  of  Captain  R.  F.  Scott,20  a  Ger- 
man under  command  of  Professor  Erich  v.  Drygalski,21  and 
a  Swedish  under  Dr.  Otto  Nordenskiold.22  A  Scotch  explor- 
ing expedition  commanded  by  Bruce,23  and  a  French  explor- 
ing vessel  under  the  command  of  Charcot 24  soon  followed. 
The  altogether  exceptional  importance  of  the  results  obtained 
by  the  British  expedition  under  Scott  led  Lieutenant,  now 
Sir  Ernest  Shackleton,  to  fit  out  at  his  own  expense  the  expe- 
dition which  for  scientific  results  as  well  as  for  an  exhibition 
of  fortitude  in  the  face  of  exceptional  difficulties,  takes  the 
first  rank  in  Antarctic  discovery.25 

It  should  not,  however,  be  overlooked  that  the  "  Chal- 
lenger "  exploring  expedition,  while  undertaken  primarily 
for  other  than  Antarctic  exploration,  entered  Antarctic 
waters  in  1874,  crossed  the  Antarctic  Circle,  and  has  fur- 
nished especially  valuable  data  upon  the  pack  and  berg  ice 
of  that  region.26 


192        CHARACTERISTICS  OF  EXISTING  GLACIERS 

Before  the  exploring  expeditions  of  1838  to  1841  had  been 
undertaken,  much  had  been  learned  from  the  reports  of 
enterprising  seal  hunters  in  the  Antarctic,  such,  for  example, 
as  the  Englishmen  Biscoe,  Kemp,  and  Weddell,  and  the 
Americans  Palmer,  Pendleton,  and  others.  It  is  certain 
that  as  early  as  1812  an  American  sealing  station  was  main- 
tained in  West  Antarctica.27  Kemp  and  Enderby  Lands 
situated  in  longitude  80-90°  W.,  and  upon  the  Antarctic 
Circle  were  discovered  in  this  way  and  are  no  doubt  continued 
westward  to  the  point  earlier  reached  by  Cook  (see  Fig.  100). 

The  expeditions  of  1838-1841  were  the  first  which  really 
discovered  with  certainty  the  Antarctic  continent,  though  it 
is  now  clear  that  Cook  was  in  1774  upon  its  borders.  What 
has  been  designated  Wilkes  Land  was  skirted  by  Captain 
Wilkes  from  about  110°  to  145°  East  in  close  correspondence 
with  the  Antarctic  Circle.  Here  either  an  undulating  high 
snow  surface  which  Wilkes  interpreted  as  a  buried  mountain 
range,  or  a  high  ice  cliff  rising  abruptly  from  the  sea,  was  all 
that  could  be  made  out,  and  in  the  fierce  storms  and  almost 
continual  fogs  which  he  encountered,  seeing  conditions  were 
most  unsatisfactory.  Ross,  Borchgrevink,28  and  Scott 29 
have  all  in  turn  sailed  over  the  eastern  portion  of  Wilkes 
Land,  and  we  now  know  that  the  coast  does  not  here  extend 
along  the  Antarctic  Circle  as  was  supposed  by  Wilkes.  The 
Balleny  Islands  being  near  the  coast  as  traced  by  Wilkes, 
it  is  altogether  probable  that  in  the  bad  weather  which  he 
encountered,  these  islands  were  mistaken  for  the  continuation 
of  the  Antarctic  continent.30  Von  Drygalski  has  shown  how 
easy  it  was  for  Wilkes  to  have  been  mistaken  in  the  loom 
of  the  continent  under  the  conditions  which  he  encountered.31 
It  is  now  probable  that  the  coast  line  extends  from  near 
Wilkes'  Cape  Carr  in  a  more  or  less  direct  course  to  Cape 
North  in  Victoria  Land. 

The  same  coast  which  Wilkes  imperfectly  and  at  great 


ANTARCTIC   CONTINENT  AND  ITS  SEA-ICE  GIRDLE     193 

risk  to  his  vessels  charted  for  1500  miles,  was  seen  also  by 
D'Urville  commanding  the  French  expedition;  and  on  the 
supposition  that  the  land  was  seen  by  him  a  day  earlier 
than  by  Wilkes,  Scott  and  Shackleton  have  each  upon 
their  maps  replaced  the  name  Wilkes  Land  by  Adelie  and 
Clarie  Land,  these  being  the  names  given  by  the  French 
commander.  It  has  since  been  most  conclusively  shown 
that  owing  to  D'Urville's  failure  to  drop  a  day  from  his 
calendar  when  crossing  the  180th  meridian,  his  dates  are  in 
error,  and  Wilkes'  discovery  was  really  made  upon  the  same 
day,  but  some  hours  earlier  than  D'Urville's,32  so  closely  do 
the  two  discoveries  of  the  great  Antarctic  continent  fall 
together.  Sir  James  Ross,  experienced  explorer  as  he  was, 
and  in  ships  specially  strengthened  for  the  task  in  prospect, 
achieved  results  of  great  importance,  but  was  greatly  cha- 
grined that  he  had  been  anticipated  by  Wilkes  in  the  discov- 
ery of  the  Antarctic  continent,  and  quite  unjustly  imputed 
improper  motives  to  the  American  commander.  He  sailed 
along  the  coast  which  he  named  Victoria  Land,  with  its 
high  range  of  bare  peaks  to  which  he  gave  the  name  Admi- 
ralty Range,  and  for  500  miles  he  skirted  the  high  ice  cliff, 
since  generally  known  as  the  "  Great  Ross  Barrier  "  (see 
Fig.  100). 

Since  Ross's  time  three  new  land  areas  have  been  dis- 
covered in  the  South  Polar  region,  while  Victoria  Land  and 
West  Antarctica  have  been  much  extended  through  explo- 
ration. The  three  new  land  areas  are  King  Edward  VII 
Land,  described  by  the  English  Expedition  under  Scott, 
Kaiser  Wilhelm  II  Land,  discovered  by  the  German  expe- 
dition under  von  Drygalski,  and  Coats  Land,  which  was 
sighted  by  the  Scotch  exploring  expedition  under  Bruce 
(see  Fig.  100).  Coats  Land  was  found  upon  Weddell  Sea, 
which,  near  longitude  20°  West,  forms  a  deep  indentation  in 
the  Antarctic  continent  nearly  opposite  the  great  indenta- 


194         CHARACTERISTICS   OF  EXISTING  GLACIERS 


tion  of  Ross  Sea.    The  question  is  still  open  whether  these 
seas  may  not  eventually  be  connected  across  the  Antarctic 


FIG.  100.  —  Map  of  Antarctica  showing  the  principal  points  which  have  been 
reached  by  exploring  expeditions  and  their  relation  in  position  to  the  other  con- 
tinental masses. 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE     195 

barrier  ice.    Two  expeditions,  with  a  view  to  settle  the  ques- 
tion, are  to-day  in  prospect.33 

To  summarize,  land  has  now  been  definitely  determined 
to  exist  in  King  Edward  VII  Land  (lat.  75°  S.,  long.  150°  W.), 


FIG.  101.  —  Map  of  the  Antarctic  regions  showing  the  tracks  of  vessels.  Based 
on  Murray's  map  of  1894,  but  brought  up  to  date.  The  probable  outline  of  the 
continent  has  also  been  indicated,  largely  in  accordance  with  Murray's  view  but 
modified  to  express  later  discoveries. 


Victoria  Land  (lat.  70-80°  23'  S.,  long.  165-170°  E.),  Wilkes 
Land  (lat.  66j°  S.,  long.  110-150°  E.),  Kaiser  Wilhelm  II 
Land,  Kemp,  and  Enderby  Lands  (all  near  the  Antarctic 
Circle  and  in  longitudes  90°,  60°,  and  50°  E.),  Coats  Land 
(lat.  74°  S.,  long.  20°  W.),  and  West  Antarctica  (lat.  65-70°  S., 


196        CHARACTERISTICS  OF  EXISTING  GLACIERS 

long.  60-70°  E).  The  tracks  of  vessels  when  charted  to- 
gether (see  Fig.  101)  have  a  value  by  showing  where  the 
Antarctic  land  is  proven  not  to  extend.34  Additional  infor- 
mation concerning  the  continental  border  may  be  obtained, 
even  where  land  has  not  been  seen,  through  the  observation 
of  true  barrier  ice.  Whatever  may  be  the  origin  of  such  ice, 
in  all  cases  where  it  has  been  explored,  it  has  been  found  in 
connection  with  land  masses,  and  the  supposition  is  strong 
that  all  areas  of  true  barrier  ice  indicate  a  connection  with 
land  masses.  Captain  Cook  in  1773,  when  near  the  Antarc- 
tic Circle,  and  in  longitude  40°  E.,  saw  a  uniform  and  level 
mass  of  ice  extending  along  the  horizon,  which  by  imperfect 
methods  he  estimated  to  be  15-20  feet  high.  This  was  cer- 
tainly not  pack  ice.35  Biscoe,  in  1831,  saw  at  a  point  some- 
what east  of  Cook's  position  a  perpendicular  wall  of  ice 
between  100  and  110  feet  in  height.  Again,  Kemp,  in  1833, 
at  a  point  still  farther  to  the  eastward,  discovered  Enderby 
Land,  which,  so  far  as  he  then  knew,  might  be  an  island,  but 
connected  with  the  discoveries  of  Cook  and  Biscoe,  and 
interpreted  with  our  present  knowledge,  this  barrier  ice  was 
clearly  part  of  the  fringe  surrounding  the  Antarctic  continent. 
The  Submerged  Continental  Platform.  — Wilkes  was  care- 
ful to  confirm  his  discovery  of  the  Antarctic  continent  by  a 
series  of  soundings  which  indicated  the  existence  of  a  sub- 
merged platform  upon  the  margin  of  the  continent.  Ross 
obtained  off  Victoria  Land  and  also  near  the  Ross  barrier 
depths  of  100  to  500  fathoms,  so  that  together  the  observa- 
tions indicated  the  presence  of  a  continental  shelf,  bordering 
the  Antarctic  continent  in  these  longitudes.36  Arctowski,37 
from  the  soundings  taken  by  the  "  Belgica  "  expedition  to  the 
westward  of  West  Antarctica,  discovered  a  similar  sub- 
merged platform,  which  at  its  outer  edge  descended  rapidly 
from  less  than  300  to  more  than  1400  fathoms  (see  Fig.  102). 
That  the  platform  is  at  its  margin  more  than  twice  the  usual 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE     197 

depth  of  continental  shelves,  Arctowski  interprets  as  evi- 
dence of  a  general  submergence  of  the  region.  If  this  inter- 
pretation is  correct,  the  amount  of  submergence  is  probably 
even  greater  than  the  figures  would  indicate,  for  the  sound- 


1539, 


950 


FIG.  102.  —  Soundings  over  the  continental  platform  to  the  westward  of  West 
Antarctica  (after  Arctowski). 


ings  of  the  "  Challenger  "  farther  to  the  westward  showed 
that  the  ocean  bottom  is  there  strewn  with  glacial  debris, 
due,  doubtless,  to  the  transporting  action  of  drifting  ice- 
bergs.38 

The  latest  French  Antarctic  expedition  has  taken  sound- 
ings over  a  portion  of  the  platform  examined  by  the  "  Bel- 
gica,"  and  shown  that  it  is  characterized  by  rather  remark- 
able irregularities  of  surface.  Farther  to  the  westward  along 
the  parallel  of  70°,  and  hence  outside  this  shelf,  a  profound 
fosse  with  depths  in  excess  of  5000  metres  was  discovered, 
though  this  decreased  in  depth  to  the  westward  near  the 
longitude  of  126°  W.39 

The  Scotch  Antarctic  expedition,  when  off  Coats  Land, 
found  the  bottom  shelving  very  markedly  to  depths  of  161 
and  159  fathoms,  which  soundings  were  obtained  some  two 


198        CHARACTERISTICS  OF  EXISTING  GLACIERS 

miles  off  the  land.  Then,  within  a  distance  of  50  sea  miles, 
the  bottom  dropped  from  131  to  2370  fathoms,  thus  showing 
that  in  this  district  also  the  slope  bordering  the  submerged 
Antarctic  platform  descends  into  great  depths.40 

The  winter  station  of  the  "  Gauss  "  within  the  sea  ice 
north  of  Kaiser  Wilhelm  Land,  was  over  a  great  submarine 
plateau,  the  depths  of  which,  as  shown  by  soundings  made 
while  approaching  and  retiring  from  the  position,  ranged 
from  130  to  375  fathoms.  Directly  beneath  the  station 
stretched  a  submarine  ridge  which  may  perhaps  have  repre- 
sented a  moraine.  On  the  edge  of  this  platform,  the 
"  Gauss  "  determined  the  same  abrupt  descent  to  consider- 
able depths  which  had  before  been  found  by  the  "  Belgica  " 
farther  to  the  eastward.  At  points  quite  near  each  other, 
the  "  Gauss  "  determined  depths  of  241  and  2890  metres, 
and  at  another  place  of  382  and  1103  metres.41  Unlike 
Arctowski,  who  assumed  a  subsidence  of  the  platform  to 
account  for  its  unusual  depth,  Philippi  has  interpreted  this 
as  evidence  that  the  platform  was  planed  down  by  the 
ice  from  the  usual  depth  of  about  100  fathoms  when  the 
ice  front  extended  to  and  beyond  the  border  of  the  platform. 
He  points  out  that  the  general  effect  of  the  retirement  of  an 
ice  sheet  is  to  induce  elevation,  rather  than  subsidence. 

The  Zone  of  Sea  and  Pack  Ice.  —  The  sea  ice  of  the  South 
Polar  region  encircles  the  Antarctic  continent  with  outlines 
roughly  parallel  to  its  borders.  Sea  ice  is  due  to  the  freezing 
of  the  surface  of  the  sea  during  the  winter  months.  Ross's 
observations,  but  particularly  those  of  the  "  Challenger  " 
expedition,42  show  that  a  wedge-shaped  mass  of  cold  water 
extends  in  the  sea  through  about  12°  of  latitude,  the  thin 
northern  edge  terminating  about  latitude  53°  S.  Within 
this  wedge  the  temperature  varies  from  28°  F.  at  the  thick 
southern  end  to  32.5°  F.  at  the  thin  northern  end.  The 
overlying  warmer  layer  of  water  has  temperatures  varying 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE     199 

from  32°  to  35°  F.,  which  represents  also  the  range  of  tem- 
perature of  the  water  below  the  cold  intermediate  wedge. 
During  the  winter,  the  warm  surface  layer  is  probably  absent, 
and  in  summer,  as  already  indicated,  this  upper  layer  thins 
toward  the  south  so  as  to  reach  the  surface  at  about  latitude 
65°  S.43  Over  the  continental  platform  to  the  westward  of 
West  Antarctica,  Racovitza  found  that  the  wedge-shaped 
cold  layer  of  water,  here  forming  the  surface,  had  a  tempera- 
ture of  —  2°  C.  (28j°  F.),  and  was  thickest  at  the  southern 
end  (lat.  31°  1'  S.),  and  that  below  this  wedge  the  tempera- 
tures increased  gradually  as  far  as  the  bottom,  where  they 
ranged  from  0°  to  - 1°  C.  (32°  to  33f°  F.).  Above  this  con- 
tinental plateau  the  cold  water  layer  is  thicker  than  the 
warmer  bottom  layer.44 

At  Cape  Adare  (lat.  71°  15'  S.)  the  water  of  the  upper 
layer  remained  constant  at  temperature  27.8°  F.  (  —  1.5°  C.) 
whenever  the  surface  was  frozen.45  At  Wandel  Island  during 
all  the  cold  winter  weather  while  the  French  expedition  was 
there,  the  sea  water  near  the  surface  remained  remarkably 
constant  at  temperature  —1.7°  to  —  1.9°C.46 

The  term  "  field-ice  "  in  the  Antarctic  regions  applies  to 
the  uniform  sheet  of  frozen  sea.  During  the  formation  of 
this  surface  ice,  some  of  the  sea  salts  are  squeezed  upward 
through  capillary  cracks  to  the  surface  and  there  freeze  as 
cryohydrates,  which  become  the  nuclei  for  further  growth 
from  atmospheric  water  vapor.  In  this  way,  beautiful 
rosette-like  aggregates  of  crystals  are  produced.47 

The  thickness  of  the  sea  ice  becomes  a  matter  of  con- 
siderable importance  in  the  study  of  Antarctic  barrier  ice 
soon  to  be  considered,  for  it  is  probable  that  sea  ice  on 
which  snow  accumulates  may  reach  almost  any  thickness, 
the  ice  being  forced  down  below  sea  level  by  the  weight  of 
the  overlying  snow.  Under  favorable  conditions  this  ice  is 
later  melted  both  from  the  bottom  in  the  water,  and  from 


200        CHARACTERISTICS  OF  EXISTING  GLACIERS 

the  surface  in  the  air.48  This  matter  will  be  more  fully  dis- 
cussed when  the  origin  of  the  barrier,  or  shelf  ice,  of  the 
Antarctic  regions  is  considered. 

Where  exposed  to  the  wind,  however,  snow  does  not 
generally  accumulate  upon  smooth  ice,  in  which  case  its 
thickness  is  probably  quite  moderate.  A  thickness  of 
8J  feet  is  the  largest  that  was  measured  by  the  Scott  expedi- 
tion,49 while  7  feet  is  the  maximum  reported  by  Shackleton.50 
These  values  were,  however,  obtained  in  exceptionally 
high  southern  latitudes,  and  are  much  in  excess  of  those 
which  have  been  measured  outside  of  the  Ross  sea.  Thus 
the  greatest  thickness  measured  by  Gourdon  near  Wandel 
Island  was  16  inches.51 

Not  only  is  the  thickness  of  the  sea  ice  sometimes  much 
increased  through  snowfall,  but  when  broken  up  in  the 
spring  to  form  the  pack  ice,  some  layers  are  forced  beneath 
others  and  the  whole  is  frozen  into  a  compact  mass  of  much 
greater  thickness.  Thus  blocks  are  built  up  to  form  slabs 
(Schollen  ice)  which  may  be  25>feet  or  more  in  height.52 

The  cover  of  sea  ice  is  subject  to  drift  due  to  air  currents 
blowing  over  it,  and  this  has  special  interest.  Where 
explored  by  the  "  Belgica  "  expedition,  the  coming  of  wind 
was  foretold  by  pressures  within  the  ice.  It  was  found  that 
during  calm  weather  there  was  always  a  change  in  the  pack 
accompanied  by  cracks  and  open  lanes,  or  leads.  The 
pressure  is  produced  afterwards,  though  before  the  wind  is 
felt.  Still  later  the  wind  arrives,  and  the  pressure  soon 
thereafter  ceases,  when  the  ice  pack  is  found  to  be  drifting.53 
The  pressure  in  the  ice  would,  therefore,  appear  to  be  due  to 
the  friction  of  the  wind  upon  the  upper  surface  near  the  wind- 
ward side  of  the  mass  forcing  that  portion  forward  upon  the 
lee  portion,  or  in  some  cases  against  a  shore. 

This  discovery  that  the  principal  cause  of  the  crushing 
within  the  pack  is  the  distant  approach  of  wind  has  great 


ANTARCTIC   CONTINENT  AND   ITS  SEA-ICE  GIRDLE     201 


interest  in  showing  that  the  inertia  of  rest  possessed  by  such 
a  large  body  of  ice  —  the  excess  of  the  starting  friction  over 
sliding  friction  —  induces  a  tremendous  compressive  stress 
within  this  great  ice  raft  along  the  wind  direction.  The  wind 
having  exerted  its  frictional  stress  over  a  relatively  small 
area  near  the  distant  windward  margin,  the  crushing  condi- 
tions are  similar  to  those  which  exist  in  a  long  line  of  freight 
cars  suddenly  struck  and  pushed 
forward  by  a  powerful  engine  at 
the  distant  end. 

The  brittleness  of  ice  at  low 
temperatures  makes  it  pertinent  to 
consider  these  effects  of  compres- 
sion within  the  pack  in  connection 
with  the  well-known  experiments 
of  Daubree  and  Tresca  upon  blocks 
of  moulder's  wax.54  A  block  of 
this  material  in  the  form  of  a  rec- 
tangular prism  was  compressed 
between  the  jaws  of  a  testing 
machine  and  found  to  yield  by 
rupture  in  a  network  of  cracks 
which  were  plane  surfaces  perpen- 
dicular to  the  free  surface  of  the 
block  and  arranged  within  two  sets 
or  series,  which  were  approximately 
perpendicular  to  each  other,  though 
inclined  45°  to  the  direction  of  com- 
pression (see  Fig.  103). 

Theoretically  in  a  body  which 
varies  considerably  from  perfect 
elasticity,  there  would  be  a  larger  angle  than  this  with  the 
direction  of  compression,  because  of  lateral  yielding.  Test 
blocks  of  cement,  for  example,  when  similarly  tested,  show 
much  larger  angles  between  the  fracture  planes. 


FIG.  103.  —  Cracks  formed  on 
the  free  surface  of  a  block  of 
moulder's  wax  when  crushed 
in  a  testing  machine  (after 
Daubr6e  and  Tresca). 


202         CHARACTERISTICS  OF  EXISTING  GLACIERS 


Arctowski,  as  a  result  of  protracted  studies  upon  the  ice- 
pack to  the  west  of  West  Antarctica,  found  that  the  forms  of 
the /zigzagging  open  lanes  of  water,  and  the  lakes  which  are 
found  within  the  pack,  are  both  best  explained  by  as- 
suming the  pack  to 


cz. 


6, 


be  made  up  of  an 
aggregation  of  simi- 
lar quadrangular  ele- 
ments which  compose 
elements  of  similar 
form,  but  of  higher 
order  of  magnitude. 
When  the  pack  is 
subjected  to  traction, 

^  j^y  wjnc[g  passing 
'  . 

off  its  Surface,  the 
water  jeadg  n  m 

t       r 

parallel  series,  first  in 
one  and  later  in  another  direction,  though  the  larger  rafts 
continue  to  maintain  a  quite  remarkable  constancy  of  orien- 
tation (see  Fig.  104)  ,55 
That  the  neighboring  lanes  within  the  pack  are  essentially 


FIG.  104.  —  Open  lane  of  water  within  the  Antarctic 
pack  ice  showing  the  minor  elements  of  similar 
form  which  are  believed  to  be  responsible  for  the 
zigzagging  courses  of  the  water  lanes  (after  Arc- 
towski). 


FIG.  105.  —  Lozenge-shaped  lakes  within  the  pack  arranged  en  echelon,  and 
believed  to  be  due  to  separation  and  subsequent  junction  of  the  pack  after  a 
differential  shearing  motion  with  reference  to  the  line  of  rupture,  the  pack  being 
already  divided  into  lozenge-shaped  sections  as  a  result  of  compression  (after 
Arctowski). 

parallel  was  believed  to  be  confirmed  by  the  observation  of 
parallel  ribbons  of  "  water  sky  "  in  so  many  cases. 


ANTARCTIC   CONTINENT  AND  ITS  SEA-ICE  GIRDLE     203 

Moreover,  the  lakes  of  open  water  which  are  found  within 
the  pack  have  quite  generally  a  quadrilateral  outline,  and 
could  sometimes  be  seen  to  have  their  sides  extended  by 
long  rectilinear  cracks  (see  Fig.  105). 

This  tendency  of  broadly  extended  ice  plates  to  separate 
into  prismatic  blocks  is  also  common  to  the  margin  of  the 
shelf  ice  soon  to  be  considered.  A  case  where  half  submerged 
glacier  ice  has  been  compressed  against  an  obstructing  island 
and  subsequently  broken  away  so  as  to  leave  on  open  strait 
between,  reveals  the  same  vertical  fissures  and  the  peculiar 
zigzags  as  well.56 

The  thickened  sea  ice  of  Posadowsky  Bay  near  its  eastern 
margin  has  a  zigzag  outline,  and  there  is  found  a  series  of 
cracks  parallel  to  the  northern  edge,  to  which  cracks  corre- 
spond in  direction  parallel  ridges  of  hummocks  and  ranks  of 
thickly  packed  icebergs.57  This  ice  is  stranded  through  the 
icebergs  on  shallows  of  the  bay,  and  v.  Drygalski  believes 
that  the  wind  friction  upon  the  mass  is  the  direct  cause  of  the 
phenomena.  The  outer  edge,  which  is  thickened  sea  ice, 
changes  its  position  from  year  to  year,  new  ice  being  some- 
times added  to  extend  the  mass,  and  at  other  times  strips 
being  separated  by  traction  of  the  wind  to  float  northward 
with  the  drifting  pack. 

While  the  drifts  of  the  pack  in  which  the  "  Belgica  "  was 
frozen  extended  through  25°  of  longitude,  its  differential 
motions  appear  to  have  been  small.  The  pack  and  schollen 
ice  to  the  north  of  Kaiser  Wilhelm  Land  where  observed  by 
the  German  expedition,  was  notably  stagnant,  since  the 
"  Gauss  "  maintained  its  position  for  many  months.  Under 
such  circumstances  icebergs  frozen  into  the  pack  maintained 
their  relative  positions  for  long  periods,  and  the  snow  chased 
by  the  wind  was  arranged  in  long  parallel  sastrugi  of  great 
perfection  (see  Fig.  106)  ,58  Although  in  both  these  localities 
unusually  quiet,  elsewhere  sea  ice  has  been  seen  to  undergo 


204         CHARACTERISTICS  OF  EXISTING  GLACIERS 


complex    differential,    so-called    "  screwing "    movements, 
which  result  in  the  well-known  pressure  ridges.     Some  of 

these  form  from  essen- 


tially  the  same  causes 
as  those  on  the  surface 
of  small  inland  lakes  of 
the  temperate  regions. 
During  a  fall  of  temper- 
ature the  ice  contracts, 
thus  opening  fissures 
and  leads,  which  in  the 
low  temperatures  are 
quickly  healed  by  the 
formation  of  new  ice. 
The  next  rise  of  tem- 
perature with  the  re- 
sulting expansion  of  the  ice,  introduces  powerful  internal 
stresses  which,  taking  advantage  of  the  relatively  weak 
"  planks  "  of  new  ice  within  the  fissures,  buckles  them  up 
into  overfolds  and  overthrust  faults.  The  more  important 
"  hummocks  "  upon  the 
surface  of  the  sea  ice  result, 
however,  from  wind  friction 
upon  its  surface  (see  Figs. 
107  and  108).  Borchgre- 
vink  has  thus  described 
this  phenomenon : 59  — 


FIG.  106.  —  Sastrugi    on   Schollen   ice    as   seen 
from  a  balloon  (after  Von  Drygalski). 


•^  ••    s  -jJt  •f^i^ 


FIG.  107.  —  Pressure  lines  upon  the  sur- 
face of  sea  ice  (after  Shackleton) . 


In  the  evening,  May  5th, 
.  .  .  we  heard  roaring  and 
crushing  to  the  N.W.  of  our 

peninsula,  and  when  we  came  near  the  beach  we  witnessed  a 
scene  of  singular  grandeur.  The  ice-fields  were  screwing  and  at 
the  beach  the  pressure  must  have  been  tremendous.  Already  a 
broad  wall  some  30  feet  high  rose  the  whole  length  of  the  N.W. 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE    205 


beach,  and  coming  nearer  we  saw  that  the  whole  of  this  barrier 
was  a  moving  mass  of  ice  blocks,  each  several  tons  in  weight.     The 
whole  thing  moved  in  undulations,  and  every  minute  this  live 
barrier  grew  in  height  and  precipi- 
tated large  blocks  on  to  the  peninsula 
where   we   watched   the    interesting 
phenomena  from  the  distance  of  a 
few  yards.     The  roar  of  the  screwing 
was  appalling. 

The  "Antarctica/7  returning  to 
Snow  Hill  Island  at  the  end  of 
the  winter  in  order  to  take  off 
the  Swedish  Expedition,  was 
nipped  in  the  pack  ice,  and  its  sides  yielding  to  the  pres- 
sure, it  sank  so  soon  as  a  shift  in  the  pack  had  released  it 
from  its  position.  This  pressure  upon  the  ship  was  devel- 
oped suddenly,  "  the  ship  began  to  tremble  like  an  aspen 
leaf,  and  a  violent  crash  sent  us  all  up  on  deck  to  see 
what  the  matter  was.  The  pressure  was  tremendous;  the 
vessel  rose  higher  and  higher,  while  the  ice  was  crushed  to 
powder  along  her  sides."  60  Later  there  was  a  second  crash 
and  the  ship's  sides  were  crushed  in  (see  Fio\  109). 


FIG.  108.  —  Pressure  ridge  formed 
on  the  shore  of  Victoria  Land 
(after  Borchgrevink) . 


FIG.  109.  —  Sinking  of  the  "Antarctica  "  (after  Anderson). 

The  experiences  of  the  crew  of  the  "  Antarctica  "  after  the 
abandonment  of  their  vessel  furnish  us  the  best  record  of  the 
manner  in  which  the  pack  is  broken  up  in  the  spring  into 


206         CHARACTERISTICS  OF  EXISTING  GLACIERS 

great  floes  that  are  carried  first  in  one  direction  and  then  in 
another  by  the  shifting  winds.  New  leads  suddenly  open 
at  unexpected  places,  and  a  little  later  are  as  suddenly  closed, 
sending  up  pressure  ridges  and  hummocks  upon  the  ice  sur- 
face.61 

On  Ross  Sea  the  gales  grow  excessively  violent  towards  the 
end  of  September  and  in  October  (the  Southern  spring),  and 
by  this  time  the  sea-ice  sheet  has  probably  commenced  to 
weaken.  The  general  break  up  of  its  surface  was  twice  ob- 
served by  sledge  parties  connected  with  the  Scott  Antarc- 
tic expedition.62  On  one  day  the  sea  would  be  seen  com- 
pletely covered  with  ice,  and  on  the  next  appear  as  a  clear 
sheet  of  open  water.  Once  freed,  the  ice  drifts  northward 
and  forms  that  heavy  belt  of  pack  ice  which  hems  in  the  Ant- 
arctic. Inasmuch  as  the  small  detached  masses  of  ice  move 
faster  than  the  main  sheet,  these  float  in  advance  upon  the 
north  side  like  a  line  of  outposts,  whereas  in  the  south  and 
rear  there  is  a  jam  with  loose  pieces  crowding  hard  upon  the 
pack.  Amundsen  has  called  attention  to  a  striking  con- 
trast between  the  pack  ice  of  the  Antarctic  regions  and  that 
of  the  northern  hemisphere,  due  to  the  more  rapid  currents 
in  the  Arctic  seas.  While  we  find  in  the  Arctic  ice  channels 
and  lakes  several  miles  in  length,  no  similar  formations  are 
common  in  the  South  Polar  region.  Amundsen  believes  that 
the  "  indolence"  of  the  ice  in  which  the  "  Belgica"  was  im- 
prisoned is  explained  by  the  weak  currents  flowing  beneath 
it.63 

The  manner  of  formation  of  the  sea  ice  has  been  described 
in  some  detail  among  others  by  Gourdon,  who  says : 64  — 

With  great  cold  the  sea  smokes  like  a  furnace  because  of  the 
great  difference  between  the  water  temperature  and  that  of  the 
atmosphere.  Its  surface  becomes  glistening  like  that  of  oil.  Mi- 
nute needles  of  ice  appear,  which  multiply  rapidly  and  become 
united  into  a  firm  network.  The  rate  of  accretion  which  I  have 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE    207 

been  able  to  follow  by  cutting  little  rectangles  in  the  ice  near  the 
boat  is  very  rapid  during  the  first  hours  of  its  formation.  The 
thickness  often  attains  6  to  7  centimeters  (2J4  to  3  inches)  in  a  few 
hours.  After  that  the  increase  goes  on  more  and  more  slowly. 
The  first  beds  formed  are  an  insolator  which  protects  the  subjacent 
water,  so  that  to  attain  a  thickness  of  12  to  15  centimeters  (5  to  6 
inches)  requires  several  days.  The  ice  of  the  first  hours  has  a  platy 
structure,  being  formed  of  small  lamellae  which  imprison  between 
them  a  little  brine.  The  sea  water  in  freezing  throws  off,  in  fact, 
a  large  part  of  the  salt  which  it  contains ;  these  separated  portions 
having  a  saline  concentration  which  lowers  their  freezing  point. 


This  ice  is  pliable  and  plastic :  a  thickness  of  even  a  number 
of  centimeters  undulates  with  the  movements  of  the  swell.  If  the 
cold  persists,  it  becomes  compact,  and  with  temperatures  below 
-20°  C.  (-4°  F.)  it  is  hard,  brittle,  and  sonorous  under  the  blows  of 
the  pickaxe.  Its  transparency  gives  it  a  black  appearance  in  con- 
trast with  the  snow  which  covers  it. 

It  is  somewhat  surprising  to  note  what  small  thicknesses 
of  sea  ice  are  formed  in  those  cases  where  no  snow  has  been  de- 
posited upon  the  surface.  This  has  now  been  learned  on  the 
basis  of  discoveries  by  Nansen,  Peary,  and  others  within  the 
Arctic  regions.  The  greatest  thickness  measured  by  Gour- 
don  near  Wandel  Island  was  a  little  in  excess  of  16  inches. 

Thus  sea  ice  differs  from  lake  ice  in  that  it  does  not  form  in 
vertical  prisms,  as  does  lake  ice.  According  to  Mawson65  the 
ice  begins  to  form  in  scale-like  crystals  perhaps  an  inch  in 
diameter,  which  first  float  about  within  a  few  feet  of  the  sur- 
face. Through  the  motion  of  the  water  these  scales  soon 
unite  to  form  rosettes,  and  when  they  have  become  sufficiently 
numerous,  these  in  turn  freeze  together  to  form  a  complete 
felt- work  upon  the  surface.  In  this  initial  stage  of  the  ice 
cover,  the  ice  is  dark  and  partially  transparent,  as  well  as 
peculiarly  flexible.  If  there  be  a  heavy  swell,  this  cover  is 
broken  into  pieces  a  foot  or  more  in  diameter,  depending 


208         CHARACTERISTICS  OF  EXISTING  GLACIERS 

upon  its  thickness  at  the  time,  and  these  cakes  by  jos- 
tling together  become  rounded  and  turned  up  at  the  edge 
-the  well-known  "  pancake  ice."  66  Eventually,  when  the 
cakes  are  again  frozen  together,  a  stronger  cover  is  pro- 
duced which  increases  in  thickness  through  the  growth  of 
vertical  ice  prisms  upon  its  lower  surface.  These  prisms 
may  be  a  half  inch  in  diameter  and  many  inches  in  length. 
Snow  falling  upon  the  surface  of  ice  increases  the  thickness  of 
the  layer,  and  if  continued  through  more  than  a  single  season, 
the  prisms  of  the  lower  layers  grow  upwards  through  re- 
crystallization.  The  salt  squeezed  out  of  the  water  during 
the  formation  of  the  prisms  remains  in  white  vertical  tracts 
between  them. 

Upon  the  landward  side  of  sea  or  pack  ice  in  contact  with 
the  shore,  there  is  generally  to  be  found  a  fringe  of  thicker  ice 
known  as  shore  ice  or  as  the  ice-foot.  This  foot  usually  rises 
to  a  height  of  6  to  10  feet  above  sea  level  and  has  the  form  of 
a  flat,  narrow  terrace  20  to  100  feet  wide  (see  plate  27  B). 
Sometimes,  however,  it  shows  a  cliff  80  to  100  feet  high  with 
a  summit  ascending  inland  in  a  more  or  less  steep  snow  slope. 
The  ice-foot  may  have  been  formed  either  by  the  freezing  of 
the  sea  water  which  dashed  as  spray  against  the  cliff,  in 
which  case  there  are  beautiful  ice  caves  lined  with  stalactites, 
but  it  is  generally  the  result  of  a  collection  of  snow  in  the  form 
of  a  drift  under  the  lee  of  the  cliff.67  If  formed  either  wholly 
or  in  part  from  snow  drift,  the  ice-foot  is  apt  to  have  alter- 
nate layers  of  compressed  snow  and  of  sand  and  gravel,  both 
alike  the  work  of  the  fierce  southerly  blizzards.  The  sea  ice, 
which  moves  up  and  down  with  the  tides,  which  on  Ross  Sea 
have  a  range  of  from  two  to  three  feet,  is  usually  separated 
from  the  shore  ice  or  ice-foot  by  one  or  'more  well-marked 
"  tide  cracks." 

The  Ice  Islands  and  Ice-foot  Glaciers.  — The  low  islands  in 
high  southern  latitudes  are  always  snow-covered,  so  that  no 


PLATE  27. 


A.    Fringing  glaciers  about  Sturge  Island,  Balleny  Group  (after  Scott). 


B.    Ice-foot  with  boat  party  landing  (after  Scott). 


PLATE  28. 


A.    Ice-dome  on  Bouvet  Island  (after  Chun). 


B.    Neve  stratification  in  ice  island  (after  Arctowski). 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE    209 

land  is  visible  ^  —  the  land  is  entirely  enveloped  in  an  ice- 
cap (see  Fig.  110).  Such  islands  from  a  half  mile  to  a  mile 
or  more  across  are  found  to  the  northward  of  King  Edward 
Land.69  Even  in  the  low  latitude  of  54°  the  volcanic  Bouvet 
Island  was  sheathed  in  snow  when  visited  by  Krech  in 


FIG.  110.  —  Ice  island  off  King  Edward  Land  (after  Scott). 

midsummer.70  The  clouds  but  partly  conceal  the  perfect 
shield  form  of  the  island  in  the  view  of  plate  28  A. 
Similar  ice  islands  have  been  described  by  Arctowski.71 
Where  these  come  down  to  the  sea,  the  ice  cliff  shows  the 
characteristic  neve  stratification  (see  plate  28  B). 

Where  the  islands  are  higher,  the  snow  either  wholly  or  in 
part  is  blown  by  the  wind  from  the  higher  surfaces  into  the 
lee  of  the  hills  and  thus  forms  a  fringing  zone  of  ice-foot. 
Such  a  fringing  ice-foot  is  illustrated  by  Sturge  island  of  the 
Balleny  Group  to  the  north  of  Victoria  Land  (see  plate  27  A).72 
The  ice-foot  surrounding  a  land  mass  represents  a  type  of 
fringing  glacier  not  unlike  those  described  by  Chamberlin 
and  Peary  from  Northern  Greenland.73  For  long  distances 
these  marginal  bands  of  rather  steeply  sloping  snow  and  ice 
bound  the  elevated  land  and  have  in  consequence  been  called 
by  Otto  Nordenskjold  ice-foot  glaciers.  They  are  obviously 
built  up  from  drift  snow  and  have  a  definitely  stratified  struc- 
ture.74 These  ice-foot  glaciers  are  what  Arctowski  has  de- 
scribed as  slope  glaciers  (Gehdngegletscher),™  and  Gourdon 
as  "piedmont  "  glaciers.76 

Upon  the  larger  islands  of  West  Antarctica  there  are 


210         CHARACTERISTICS  OF  EXISTING  GLACIERS 

found  thin  bodies  of  inland-ice  through  which  the  rock 
peaks  project  as  nunataks.  This  type  of  southern  glacier 
resembling  as  it  does  some  of  the  ice-caps  of  Spitzbergen 
has  been  designated  by  Otto  Nordenskiold  the  Spitzbergen 
type. 

REFERENCES 

1  Hobbs,  "Characteristics  of  the  Inland-ice  of  the  Arctic  Regions," 
Proc.  Am.  Phil.  Soc.,  vol.  49,  1910,  pp.  57-129,  pis.  xxvi-xxx. 

2  December,  January,  and  February. 

3  June,  July,  and  August. 

4  Otto  Nordenskiold  and  J.  G.  Andersson,  "  Antarctica,  or  Two  Years 
amongst  the  Ice  of  the  South  Pole,"  London,  1905,  pp.  159-181.    Also 
"  Die  Polarwelt,"  Leipzig  and  Berlin,  1909,  pp.  89-90. 

6  E.  v.  Drygalski,  "  Zum  Kontinent  des  eisigen  Siidens,"  etc.,  Berlin, 
1904,  p.  387. 

6  Henryk  Arctowski.     "The  Antarctic   Climate."     Published  as  Ap- 
pendix II  of  Cook's  "  Through  the  First  Antarctic  Night,"  New  York, 
1900,  p.  427. 

7  Louis  Bernaechi, "  Meteorology  and  Magnetism."   Appendix  in  Borch- 
grevink's  "  First  on  the  Antarctic  Continent,"  London,  1901,  pp.  301-310. 

8  E.  H.  Shackleton,  "  The  Heart  of  the  Antarctic,"  London,  1909,  vol.  2, 
pp.  386-389. 

9  R.  F.  Scott,  "  The  Voyage  of  the  *  Discovery,'  "  London,  1905,  vol.  2, 
pp.  208-211. 

10  Robert  C.  Mossman,  "Some  Results  of  the  Scottish  National  Ant- 
arctic Expedition,"  Scot.  Geog.  Mag.,  vol.  21,  1905,  p.  421. 

11  O.  Nordenskiold,  "Die  Polarwelt,"  p.  90. 

12  Scott,  "  Voyage  of  the  'Discovery,' "  vol.  2,  p.  261. 

13  Shackleton,  "The  Heart  of  the  Antarctic,"  vol.  1,  pp.  342-348. 

14  For  resumes  of  Antarctic  exploration  up  to  the  revival  of  interest  in 
that  region  near  the  beginning  of  the  twentieth  century,  see  Karl  Fricker, 
"  The  Antarctic  Regions,"  London,  1900,  pp.  xii  and  292 ;  also  George 
Murray  and  Sir  Clements  R.  Markham  (Editors),  The  Antarctic  Manual 
for  the  Use  of  the  Expedition  of  1901.      Issued  by  the  Royal  Geographi- 
cal Society,  London,  1901,  pp.  586.      Also  Georg  v.  Neumayer,  "Auf 
zum  Siidpol,  45  Jahre  Wirkens  zur  Forderung  der  Erforschung  der  Siid- 
polarregion,  1855-1900,"  Berlin,    1901,  pp.  1-483.     Also    E.  S.  Balch, 
"Antarctica,"    Philadelphia,    1902,  pp.    230.     Also   Hugh   Robert   Mill, 
"The  Siege  of  the  South  Pole,"  London,  1905,  pp.  1-450.     Later  expedi- 
tions have  been  treated  by  A.  W.  Greely  in  his  "  Handbook  of  Polar  Dis- 
coveries," 4th  ed.,  1909,  pp.  1-336,  in  most  respects  an  authoritative  work,, 
but  marred  by  inclusion  of  the  fictitious  polar  journey  of  the  fakir  Cook. 

15  Charles  Wilkes,  "Narrative  of  the  United  States  Exploring  Expedi- 
tion during  the  Years  1838-1842,"  especiaUy  vol.  2,  1844,  chaps.  IX-XL 
Also  Atlas. 


ANTARCTIC  CONTINENT  AND  ITS  SEA-ICE  GIRDLE     211 

16  J.  S.  C.  Dumont  d'Urville,  "Voyage  au  Pole  Sud  et  dans  1'Oceanie." 
1841-1854,  vols.  2  and  8  and  Atlas. 

17  J.  C.  Ross,  "Voyage  of  Discovery  and  Research  to  the  Southern  and 
Antarctic  Regions,"  2  vols.,  1846. 

18  C.  E.  Borchgrevink,  "First  on  the  Antarctic  Continent,  being  an 
Account  of  the  British  Antarctic  Expedition,"  1898-1900,  London,  1901, 
pp.  xv  and  333. 

19  Com.  de  Gerlache,  "Quinze  mois  dans  1'antarctique,"  Paris,  1902,  pp. 
1-284.     See  also  appendices  in  Frederick  A.  Cook,  "Through  the  First 
Antarctic   Night,  1898-1899.     A   narrative  of  the  voyage  of    the  'Bel- 
gica'  among  newly  discovered  lands  and  over  an  unknown  sea  about  the 
South  Pole,"  New  York,  1900.     Appendix  I,  on  'General  Results,'  by  E. 
Racovitza;  Appendix  II,  'Antarctic  Climate/  by  H.  Arctowski;  Appen- 
dix III,  ' Bathymetrical  Conditions,'  by  H.  Arctowski;    and  Appendix 
IV,  'Navigation  of  Antarctic  Pack  Ice,'  by  R.  Amundsen. 

20  R.  F.  Scott,  "  The  Voyage  of  the  '  Discovery,' "  2  vols.,  London,  1905, 
pp.  xix,  556  and  xii,  508. 

21  E.  v.  Drygalski,  "Zum  Kontinent  des  eisigen  Siidens,  Deutsche  Siid- 
polarexpeditionen  des  'Gauss,'  1901-1903,"  Berlin,  1904,  pp.  668. 

22  N.  Otto  Nordenskiold,  and  Joh.  Gunnar  Andersson,  "Antarctica,  or 
Two  Years  amongst  the  Ice  of  the  South  Pole,"  London,  1905,  pp.  xviii 
and  608. 

23  Brown,  et  aL,  "The  Voyage  of  the  '  Scotia,'  being  the  record  of  a  voyage 
of  exploration  in  Antarctic  seas."     By  three  of  the  staff.    Edinburgh  and 
London,  1906,  pp.  xxiv  and  375. 

24  J.  Charcot,  "Le  'Francais'  au  pole  sud,"  Flammarion,  Paris,  1906. 

25  E.  H.  Shackleton,  "The  Heart  of  the  Antarctic,  being  the  story  of 
the  British  Antarctic  Expedition  1907-1909,"  2  vols.,  London,  1910,  pp. 
xi,  371  and  xv,  419. 

26  "  Report  on  the  scientific  results  of  the  voyage  of  H.  M.  S.  Challenger 
during  the  years  1873-1876,"  London,  1885,  "Narrative,"  vol.  1,  pp.  39&- 
434. 

27  This  small  area  of  land,  or  some  portion  of  it,  has  received  so  many 
names  that  it  seems  well  to  avoid  confusion  by  adopting  the  one  general 
term  which  is  without  international  significance.     TJie  names  Dirk  Ger- 
ritz  Archipelago,  Graham  Land,  Palmer  Land,  Danco  Land,  Alexander 
I  Land,  and  King  Oscar  II  Land  recall  respectively  Dutch,   English, 
American,    Belgian,    Russian   and    Swedish    affiliations  connected   with 
discovery. 

28  Borchgrevink,  1.  c.,  pp.  55-57,  2d  map  at  end  of  volume. 

29  Scott,  "Voyage  of  the  'Discovery,'"  vol.  2,  pp.  390-393.     Chart  in 
cover. 

30  It  is  clear  from  the  reading  of  Wilkes'  narrative  that  the  term  "icy 
barrier"  which  he  repeatedly  employs  should   not  be  interpreted  in  the 
technical  sense  which  it  has  since  acquired.     While  in  many  cases  it 
clearly  refers  to  true  barrier  ice,  it  is  none  the  less  evident  from  the  lan- 
guage used  that  in  other  cases  pack  ice  only  is  referred  to. 

31  "Zum  Kontinent  des  eisigen  Siidens,"  etc.,  p.  389. 


212         CHARACTERISTICS  OF  EXISTING  GLACIERS 

32  Rear  Admiral  John  E.  Pillsbury,  U.  S.  N.,  "  Wilkes'  and  D'Urville's 
Discoveries  in  Wilkes  Land,"  Nat.  Geogr.  Mag.,  vol.  21,  1910,  pp.  171-173. 

33  Wilhelm  Filchner,  A.  Penek,   et  al.,  "Plan  einer  deutschen  antark- 
tischen  Expedition,"  Zeitsch.  Gesell.  Erdkunde,  Berlin,  1910,  No.  3,  pp.  1-6 
(reprint).     Also  E.  Bruckner,  "  Filchner' s  deutsche  antarktische  Expedi- 
tion," Zeit.  f.  Gletscherk.,  vol.  5,  1910,  pp.  154-156,  fig.    Also  W.  S.  Bruce, 
"  The  New  Scottish  National  Expedition,  1911,"  Scot.  Geogr.  Mag.,  vol.  26, 
1910,  pp.  192-195. 

34  For  a  large-scale  map  showing  tracks  of  vessels  to  1905  see  H.  R.  Mill, 
"  The  siege  of  the  South  Pole,"  London,  1905,  chart  at  end. 

35  Fricker,  "  The  Antarctic  Regions,"  1900,  p.  225. 

36  See  John  Murray  and  others,  "  Scientific  advantages  of  an  Antarctic 
Expedition,"    Nature,  vol.  57,  No.  1479,  1898,  reprinted  in  Smithsonian 
Report  for  1897,  Washington,  1898,  p.  419. 

37  H.  Arctowski,  "The  Bathymetrical  Conditions  of  the  Antarctic  Re- 
gions," Appendix  III   in  Cook's  "Through  the  First  Antarctic  Night," 
pp.  436-443. 

38  John  Murray,  "The  Renewal  of  Antarctic  Exploration,"  Geogr.  Jour., 
vol.  3,  pp.  1-27.     Reprinted  in  Smithsonian  Report  for  1893,  Washing- 
ton, 1894,  p.  360.     See  also  E.  Philippi,  "  Ueber  die  Landeisbeobachtungen 
der  letzen  fiinf  Siidpolar-Expeditionen,"  Zeit.  f.  Gletscherk.,  vol.  2,  1907, 
pp.  10-11. 

39  Charcot,   "  Rapports   preliminaires   sur  les   travaux    executes    dans 
1'antarctique  de  1908-1910,"  Paris,  1910,  pp.  101-102. 

40  William  S.   Bruce,  "  Some  results  of  the  Scottish  National  Antarctic 
expeditions,"  Scot.  Geogr.  Mag.,  vol.  21,  1905,  p.  405,  map  plate  opposite 
p.  456. 

41  E.  Philippi,  I.e.,  pp.  20-21. 

42  Challenger  Report,  Narrative,  vol.  1,  pp.  417-428.     See  also  Murray 
and  others,  "  Scientific  advantages  of  an  Antarctic  expedition,"  Smithsonian 
Report  for  1897,  Washington,  1898,  pp.  418-419. 

43  The  warm  lower  stratum  is  probably  due  to  waters  heavy  in  saline 
ingredients  which  come  southward  from  the  tropics,  and,  though  diluted 
by  the  Antarctic  waters,  have  still  a  higher  density  because  of  their  saline 
content. 

44  H.  Arctowski  and  H.  R.  Mill,  "  Relations  thermiques  :  rapport  sur  les 
observations  thermometriques  faites  aux  stations  de  sondages,"  Exped. 
Antarc.  Beige,  Antwerp,  1908,  pp.  14-16,  20-24. 

45  Bernacchi,  I.e.,  p.  304. 

46  Gourdon,  I.e.,  1908,  p.  124. 

47  Douglas   Mawson,    *  Ice   and  Snow,'  in  Shackleton's  "  Heart  of  the 
'Antarctic,"  vol.  2,  p.  335. 

48Ferrar,  in  Scott's  "Voyage  of  the  'Discovery,'"  vol.  2,  p.  459. 
49  Scott,  I.e.,  vol.  2,  pp.  458-459.     See  also  Racovitza,  I.e.,  p.  417. 
60  T.  W.  E.  David,  in  App.  II  of  Shackleton,  I.e.,  vol.  2,  p.  277. 
51  Gourdon,  I.e.,  1908,  p.  125. 

62  Racovitza,  I.e.,  p.  417. 

63  Racovitza,  I.e.,  p.  417. 


ANTARCTIC   CONTINENT  AND  ITS  SEA-ICE  GIRDLE    213 

64  A.  Daubree,  "  Etudes  synthetiques  de  geologie  experimental, "  Paris, 
1879,  pp.  507-519,  pi.  II  and  figs.  93-94. 

65  H.  Arctowski,  "  Resultats  du  voyage  du  S.  Y.  Belgica  en  1897-1898- 
1899  sous  le  Commandement  de  A.  de  Gerlache  de    Gomery  ;  Oceano- 
graphie,  les  glaces,  glace  de  mer  et  banquises,"  Antwerp,  1908,  pp.  39-44. 

56  See  the  map  of  the  Sefstrom  glacier  of  Spitzbergen  in  De  Geer,  "  Guide 
de  1'excursion  au  Spitzberg,"  XIe  Cong.  Geol.  Intern.,  Stockholm,  1910, 
pi.  4. 

57  E.  v.  Drygalski,  "Das  Schelfeis  der  Antarktis  am  Gaussberg,"  Sitz- 
ungsber.  k.  bay.  Akad.  d.  Wiss.,  Math.-phys.  KL,  1910,  pp.  12-15. 

68  E.  v.  Drygalski,  I.e. 

69  Borchgrevink,   I.e.,    pp.    120-121. 

60  C.  J.  Skottsberg  in  "  Antarctica,"  I.e.,  p.  524. 

61  Skottsberg,  I.e.,  pp.  537-543. 

62  Scott,  I.e.,  vol.  2,  pp.  405-406. 

63  Roald    Amundsen,   "The    Navigation  of    the  Antarctic    Ice-pack," 
Appendix  V  in  Cook's  "Through  the  First  Antarctic  Night,"  pp.  450-451. 

64  Gourdon,  I.e.,  1908,  p.  124.     See  also  Arctowski,  I.e.,  1908,  p.  19. 

65  Douglas  Mawson   in  Shackle  ton's  "Heart  of  the  Antarctic,"  vol.  2, 
p.  337. 

66  Scoresby,  "  An  account  of  the  Arctic  Regions,"  p.  239. 

67  H.  F.  Ferrar,  I.e.,  pp.  459-460.     Mawson,  I.e.,  p.  338.     T.  W.  E. 
David,  ibid.,  pp.  279-281. 

68  O.  Nordenskiold,  "  Einige  Beobachtungen  iiber  Eisformen  und  Ver- 
gletscherung    der    antarktischen    Gebiete,"    Zeit.  f.   Gletscherk.,   vol.   3, 
1908,  p.  322. 

69  Royal  Society,  National  Antarctic  Expedition  1901-1904,  Album  of 
Photographs  and  Sketches,  London,   1908. 

70  Chun,  et  al.,  "  Wissenschaftliche  Ergebnisse  der  deutsch.   Tiefsee-Ex- 
pedition  auf  dem  Dampfer  Valdivia,  1898-1899,"  Jena,  1902. 

71  Geogr.  Jour.,  vol.   18,  1901,  pp.  370. 

72  Scott,  I.e.,  vol.  1,  p.  390  and  plate  opposite. 

73  See  Proc.  Am.  Phil.  Soc.,  vol.  49,  1910,  p.  104. 
•^  Nordenskiold,  Zeit.  f.  Gletscherk.,  I.e. 

75  H.  Arctowski,  "  Die  antarktischen  Eisverhaltnisse ;  Auszug  ausmeinem 
Tagebuch  der  Siidpolarreise   der   'Belgica,'  1898-1899,"   Pet.  Mitt.  Erg. 
144,    1903,   pp.    15,    19,  21. 

76  E.    Gourdon,   in  Charcot,   Expedition   Antarctique   Frangaise   (1903- 
1905),  Glaciologie,  Paris,  1908,  p.  110,  pi.  1,  Fig.  4,  and  pi.  x,  Fig.  35. 


CHAPTER  XIII 
THE  MARGINAL  SHELF-ICE 

Its  Nature  and  Distribution.  —  The  so-called  "barrier"  ice, 
such  as  was  without  doubt  seen  by  Cook  in  1774,  offers  one 
of  the  peculiarities  in  which  the  South  Polar  area  is  sharply 
differentiated  from  its  antipodal  region.  Nowhere  within 
the  Arctic  regions  is  there  found  to-day  anything  which  in  any 
degree  can  be  compared  to  the  Antarctic  barrier  ice.  Until 
the  British  Antarctic  Expedition  of  1901-2,  the  origin  of 
this  ice  was  a  complete  mystery,  and  even  to-day  widely 
different  interpretations  have  been  offered.  There  is,  how- 
ever, every  reason  to  believe  that  during  the  period  of 
Pleistocene  glaciation,  similar  ice  masses  occupied  the  Gulf 
of  Maine  in  Northeastern  North  America  as  well  as  the 
borders  of  the  continent  of  Greenland  and  of  Patagonia. 
It  is  this  fact,  especially,  which  lends  unusual  interest  and 
importance  to  the  study  of  the  existing  barrier  ice  of  the 
Antarctic  regions. 

At  the  outset  it  is  well  to  point  out  that  the  term  "  bar- 
rier ice  "  is  in  every  way  inappropriate  for  scientific  use, 
for  it  suggests  merely  that  this  form  of  ice  opposes  a  barrier 
to  navigation.  The  term  shelf-ice  proposed  by  Norden- 
skjold  1  is  aptly  descriptive  and  will  be  adopted  here.  The 
term  "  piedmonts  afloat  "  proposed  by  Ferrar  for  such 
masses  of  barrier  ice  on  the  margin  of  the  Ross  Sea,  has 

214 


THE  MARGINAL  SHELF-ICE 


215 


much  to  recommend  it,  but  suggests  somewhat  too  strongly 
the  identity  in  origin  with  land  piedmonts.2 

As  already  pointed  out,  both  Cook  and  Biscoe  encountered 
true  shelf  ice  to  the  westward  of  Kernp  and  Enderby  Lands 
(see  ante,  p.  196),  and  though  Wilkes  uses  the  term  "  icy 


FIG.  111.  —  King  Edward  VII  Land,  with  shelf  ice  in  front  (after  Scott). 

barrier  "  for  obstructing  ice  of  any  kind,  his  descriptions  leave 
us  in  no  doubt  that  the  shelf  ice  was  encountered  near  Cape 
Carr  in  Wilkes  Land.  The  following  extracts  from  his  nar- 
rative set  forth  the  aspect  of  this  shelf  ice  as  viewed  from 
the  sea :  — 

In  some  places  we  sailed  for  more  than  fifty  miles  together 
along  a  straight  and  perpendicular  wall  from  one  hundred  and 
fifty  to  two  hundred  feet  in  height,  with  the  land  behind  it.  The 
ice-bergs  found  along  the  coast  were  from  a  quarter  of  a  mile  to 
five  miles  in  length. 

At  10  o'clock  we  were  not  more  than  three  or  four  miles  dis- 
tant. It  appeared  prodigious.  We  saw  a  cliff  with  a  uniform 
height  of  100  to  150  feet  forming  a  long  line  westward.  .  .  . 

Discovered  a  high  barrier  of  ice  to  the  northward  with  ice 
islands  to  the  southward.  .  .  . 

The  immense  perpendicular  barrier  encountered  yesterday  was 
now  in  sight  trending  as  far  as  the  eye  could  reach  to  the 
westward.3 

A  year  later  Ross  sailed  for  a  distance  of  500  miles  along 
the  front  of  the  similar  ice  wall  which  has  since  been  named 


216         CHARACTERISTICS  OF  EXISTING  GLACIERS 

in  his  honor  the  "  Great  Ross  Barrier."  Within  the  last  dec- 
ade shelf-ice  has  been  discovered  by  the  Swedish  expedi- 
tion near  King  Oscar  II  Land,  by  the  German  expedition 
near  Kaiser  Wilhelm  II  Land,  by  the  English  Expedition  in 
King  Edward  VII  Land,  and  by  the  Scotch  Expedition  in 
Coats  Land.  The  first  two  districts  having  been  examined 
in  some  detail  upon  the  spot,  will  be  more  fully  discussed 
below  under  separate  headings.  Of  the  Coats  Land  "  bar- 
rier ""  it  is  stated  that  it  formed  the  terminal  face  or  sea 
front  of  the  great  inland  ice4  (see  Fig.  112),  which  is  also 


FIG.  112. — The  Scotia  off  Coats  Land,  the  shelf  ice  showing  to  the  right  in  the 
middle  distance  and  also  in  the  distance  (after  Bruce). 

true  of  the  shelf-ice  of  King  Edward  VII  Land.     (See  Fig. 
111.) 

The  "  Great  Ross  Barrier/'  Victoria  Land. —  In  1840 
Sir  James  Ross  skirted  for  a  distance  of  500  miles  an  ice 
cliff  which  according  to  his  estimates  had  an  average 
height  of  165  feet.  The  next  visit  to  this  ice  wall  was 
made  in  1899  when  Borchgrevink  sailed  for  some  distance 
along  its  front,5  and  in  1902  Scott  made  a  detailed  survey 
of  its  entire  length  (see  Fig.  113).6  The  appearance  of 


PLATE  29. 


A.    The  margin  of  the  Great  Ross  Barrier  (after  Scott). 


B.    Near  view  of  the  Great  Ross  Barrier  where  highest,  280  feet  (after  Scott). 


THE   MARGINAL  SHELF-ICE 


217 


this  mighty  ice  cliff  as  seen  from  the  sea  is  brought  out 
to  advantage  in  Plate  28  A  and  B.  The  height  when 
observed  from  a  short  distance  appears  remarkably  uni- 


FIG.  113.  —  Map  of  the  Great  Ross  Barrier  showing  heights  of  the  cliff  in  feet  and 
soundings  of  the  sea  in  fathoms.     Full  line  is  track  of  "  Discovery  "  (after  Scott). 

form,  though  on  approaching  nearer  it  is  seen  to  vary 
from  50  to  280  feet,  and  in  places  is  even  lower  than  the 
minimum  figure  given.  Scott  mentions  a  locality  where  the 
ice  face  is  so  low  that  one  could  step  from  the  rail  of  the 
"  Discovery  "  directly  on  to  the  summit  of  the  barrier.7 
(See  Fig.  115  a.)  A  higher  edge  is  represented  in  Fig.  115  6; 
in  which  the  "  Discovery  "  is  seen  against  the  ice  cliff  within 
a  narrow  cove  of  the  ice  margin. 


FIG.  114.  —  Section  along  the  Ross  Barrier  edge  based  on  Scott's  figures  and  show- 
ing the  underlying  water  layer  upon  the  assumption  that  the  submerged  and 
emerged  portions  of  the  ice  are  in  the  ratio  by  volume  of  5  to  1. 

Examination  of  the  perpendicular  face  of  the  Ross  Bar- 
rier shows  clearly  that  its  structure  is  quite  different  from 


218         CHARACTERISTICS  OF  EXISTING  GLACIERS 

that  of  true  glacier  ice.  It  is  an  immensely  thick  formation 
of  snow  horizontally  stratified.  Even  at  a  great  distance 
its  horizontal  upper  surface,  its  vertical  fractures,  and  its 
dazzling  whiteness,  all  distinguish  it  from  ordinary  glacier 
ice.  Studied  in  detail  at  different  levels,  it  is  seen  that 
pressure  has  transformed  the  snow  grains  into  neve  snow,  the 
granules  of  which  increase  in  size  and  are  more  intimately 
interlocked  toward  the  bottom  of  the  cliff.  In  the  upper 
portions  particularly  the  snow  is  porous,  and  hence  im- 
prisons a  large  quantity  of  air.  A  study  of  bergs  derived 
from  the  barrier  which  had  floated  into  McMurdo  Sound 
where  they  were  frozen  into  the  sea-ice,  showed  that  ex- 
cept where  spray  had  frozen  over  the  surface  they  con- 
tained no  solid  ice  whatever  in  the  levels  above  the  sea 
surface.  Inasmuch  as  they  were  much  tunnelled  by  sea 
caves,  it  was  possible  to  follow  the  study  well  into  the 
interior.  Everywhere,  however,,  they  showed  only  com- 
pressed snow.8 

The  specific  gravity  of  the  shelf  ice  must  as  a  consequence 
be  much  below  that  of  true  glacier  ice,  so  that  the  barrier, 
if  afloat,  should  float  relatively  high.  Scott  estimates  that 
fully  one-fifth  of  the  mass  must  be  above  the  water  surface. 
Even  this  proportion  may  not  fairly  represent  the  buoyancy 
of  shelf  ice,  for  Captain  Evans  of  the  "  Nirnrod  "  took 
soundings  around  a  typical  tabular  iceberg  derived  from 
the  barrier,  and  found  that  although  its  height  was  80  feet, 
it  was  aground  in  water  of  the  same  depth.9  In  this  case, 
therefore,  half  the  mass  projected  above  the  water.  Off  the 
Ross  Barrier,  Sir  James  Ross  obtained  soundings  of  1360, 
1800,  and  2400  feet,10  and  more  recently  Scott  has  shown  by 
soundings  that  even  if  one-fifth  only  of  the  mass  were  above 
the  water,  there  would  still  be  some  hundreds  of  fathoms 
between  its  bottom  and  the  bottom  of  the  sea  (see  Fig. 
114).  Moreover,  since  Scott's  surveys  show  that  much  of 


THE   MARGINAL  SHELF-ICE 


219 


the  cliff  is  to-day  twenty  to  thirty  miles  farther  south  than 
when  Ross  visited  it  in  1840,  these  later  soundings  are  well 


FIG.  115  a.  —  Margins  of  the  Ross  Barrier  on  Balloon  Inlet,  where  so  low  that  one 
could  embark  directly  from  the  ship's  rail. 


FIG.  115  6.  — Where  relatively  high. 


within  the  border  of  the  shelf  ice  of  the  earlier  date  (see 
Fig.  113). 


220         CHARACTERISTICS  OF  EXISTING  GLACIERS 

Further  evidence  that  the  barrier  is  afloat  is  derived  from 
the  fact  that  for  some  distance  back  from  its  edge  the  ice 
rises  and  falls  with  the  tide  and  leaves  behind  a  complex 
system  of  vertical  fractures  as  evidence. 


FIG.  116.  —  Outline  map  of  the  known  portions  of  the  Great  Ross  Barrier  showing 
the  position  of  the  outlets  from  the  ice  plateau  (based  on  Shackleton's  map). 

Although  the  Ross  Barrier  has  been  crossed  by  Scott, 
Royds,  and  Shackleton  for  long  distances  and  in  one 
case  for  over  three  hundred  miles  (see  Fig.  116),  almost 
the  whole  mass  is  believed  to  be  afloat.  Soundings  not 
being  possible  at  points  within  the  margin,  the  best  evi- 
dence is  obtained  from  its  almost  perfectly  level  surface. 
Scott  took  aneroid  readings  at  every  half  degree  of  latitude 
along  the  line  of  his  southern  journey,  and  corrected  his 
readings  by  comparison  with  the  hypsometer  and  later 
with  simultaneous  readings  of  the  barometer  made  at  the 
winter  quarters  near  Cape  Royds.  When  thus  corrected 
it  was  found  that  the  aneroid  readings  indicated  no  increase 


THE  MARGINAL  SHELF-ICE  221 

of  elevation  toward  the  South,  but  on  the  contrary,  a  slight 
and  gradual  rise  of  barometer  was  noticeable  such  as  might 
be  ascribed  to  the  gradual  advance  toward  a  fixed  area  of 
high  atmospheric  pressure.11 

Strong  confirmatory  evidence  for  the  floating  of  the  barrier 
is  derived  also  from  measurements  of  temperatures  within 
fissures  of  the  ice.  Lieut.  Royds  found  that  whereas  near 
the  visible  land  of  White  Island  the  serial  temperatures  in 
fissures  of  the  shelf  ice  fell  to  a  mean  level  of  —  9°  F.,  at  dis- 
tances of  ten  miles  off  the  island  such  temperatures  first 
fell,  but  at  greater  depths  rose,  and  at  nineteen  fathoms 
(the  limit  of  the  test)  showed  0°  F.  This  rise  in  the  tempera- 
ture with  depth  is  best  explained  through  the  approach  to  a 
water  layer  beneath  the  ice.12 

The  surface  of  the  Ross  Barrier  ice,  as  already  stated,  is 
remarkably  level.  Within  narrow  limits  this  is  well  brought 
out  in  plate  30  A  and  B,  which  represents  photographs  of  the 
surface,  in  one  case  from  a  captive  balloon.  The  statement 
requires  modification  for  those  portions  only  of  the  shelf 
ice  which  approach  the  continent.  In  part  the  Ross  Barrier 
clearly  derives  its  nourishment  from  the  inland  plateau  ice 
lying  to  the  south  and  west.  The  outlets  for  this  material 
are  great  ice  streams  (one  of  them  fifty  miles  in  width),  and  so 
unlike  any  other  known  type  of  glacier  that  they  are  deserv- 
ing of  a  new  and  technical  name.  In  the  reports  of  the 
British  expeditions  they  have  been  referred  to  as  "  in- 
lets "  because  they  offer  a  possible  ingress  to  the  plateau. 
The  term  outlet  would  better  describe  their  function  in  the 
ice  economy,  and  they  will  hereafter  be  referred  to  by  that 
term.  Off  these  great  outlets  from  the  inland  plateau  ice, 
the  surface  of  the  shelf  ice  is  found  to  be  thrown  into  long 
undulations  which  are  recognizable  for  a  distance  of  twenty 
miles  or  more.13  Elsewhere  in  the  vicinity  of  the  land  a 
similar  but  narrower  zone  of  disturbance  is  noticed,  which 


222         CHARACTERISTICS  OF  EXISTING  GLACIERS 

may  generally  be  followed  out  from  the  borders  for  a  distance 
of  ten  to  fifteen  miles.  Within  these  marginal  zones  the 
surface  of  the  ice  is  much  crevassed  and  in  striking  con- 
trast with  its  otherwise  smooth  surface.  Similar  disturb- 
ances accompanied  by  complex  crevassing  are  observed  also 
about  islands  which  project  through  the  ice  nearer  to  its 
outer  margins.  Within  a  zone  immediately  adjacent  to  the 
mountain  borders  on  the  south  and  west  and  within  the 
disturbed  zone,  there  is  a  notably  smooth  ice  surface,  which 
is  a  result  of  melting  through  radiation  from  the  rock 
surface.  The  ice  surface  is  here  in  reality  that  of  a 
frozen  lake.14 

A  motion  within  the  Ross  Barrier  was  determined  by 
Scott's  party  from  observations  at  "  Depot  A "  near 
Minna  Bluff  seventy-five  miles  or  more  from  the  cliff  edge. 
Here  during  a  period  of  13  J  months  the  movement  was 
1824  feet  in  a  direction  a  little  to  the  east  of  north  or 
toward  the  barrier  edge.  This  corresponds  to  an  annual 
rate  of  something  over  1600  feet.  The  determination  came 
about  through  an  accidental  rediscovery  of  the  station; 
but  even  more  important,  the  depot  was  again  rediscovered 
and  relocated  by  the  Shackelton  party  after  another  in- 
terval, this  time  of  over  six  years.  The  movement  during 
this  interval  amounted  to  9600  feet,  or  about  1500  feet  per 
year,  in  a  direction  east-northeast. 

This  important  verification  of  the  earlier  determination 
that  the  shelf  ice  of  the  Ross  Barrier  moves  at  a  rate  of  more 
than  four  feet  per  day,  or  nearly  four  times  as  fast  as  the  edge 
of  the  inland  ice  of  Kaiser  Wilhelm  Land,15  must  certainly 
be  accounted  of  the  greatest  importance.  If  its  cause  is 
the  contribution  of  plateau  ice  furnished  through  the  out- 
lets along  its  borders,  the  ice  in  these  must  either  have 
a  very  rapid  movement  or  be  exceptionally  important 
at  points  beyond  where  exploration  has  been  carried  to 


PLATE  30. 


Horizontal  surface  of  the  Ross  Barrier,  to  the  south  of  Minna  Bluff,  with  sastrugi 

(after  Scott). 


B.    View  of  surface  of  Ross  Barrier  taken  from  a  captive  balloon,  showing  sastrugi. 
black  spots  are  men  and  the  long  dark  lines  their  shadows  (after  Scott). 


The 


PLATE  31. 


A.    A  new  ice-face  on  the  Ross  Barrier  (after  Scott). 


B.    An  old  ice-face  on  the  Ross  Barrier  (after  Scott). 


THE  MARGINAL  SHELF-ICE  223 

the  south  of  the  Beardmore  outlet.  The  possibility  is 
not  excluded  that  the  Ross  Barrier  is  directly  connected 
with  the  shelf-ice  at  the  head  of  the  Weddell  Sea  on  the 
opposite  side  of  the  pole,  and  that  drift  sets  in  the  direction 
of  the  former. 

Although  the  shelf-ice  is  unquestionably  in  part  nourished 
by  the  outlet  glaciers  leading  down  from  the  ice  plateau  to 
the  south  and  west,  it  is  itself  a  vast  neve,  as  has  already 
been  shown  from  study  of  its  structure,  and  account  must, 
therefore,  be  taken  of  alimentation  from  the  snow  falling 
upon  its  surface. 

The  annual  snow  fall  at  Depot  A,  about  seventy-five 
miles  from  the  barrier  edge,  is  equivalent  to  1\  inches  of 
rain.  Though  usually  reckoned  as  the  equivalent  of  as 
many  feet  of  snow,  the  snow  is  here  so  compact  as  to 
possess  less  than  twice  the  volume  of  the  equivalent  water 
(or  13^  inches).16  At  Cape  Royds,  the  winter  station  near 
the  barrier  edge,  the  annual  snow  fall  was  estimated  on 
the  basis  of  measurements  as  the  equivalent  of  9J  inches  of 
rain.  These  figures,  however,  like  those  obtained  at  Depot 
A,  include  drift  snow,  and  there  is  no  means  of  telling  what 
proportion  of  the  total  was  locally  derived  and  what  was 
brought  from  a  distance  by  the  winds.  Although  still  heavier 
falls  are  assumed  for  the  Drygalski  ice  barrier  tongue  to  the 
northward,  it  should  be  noted  that  at  Cape  A  dare  where  the 
likelihood  of  collecting  drift  is  comparatively  small  (lat. 
71°  15'  S.),  the  snow  collected  by  the  gauges  of  the  Borch- 
grevink  party  during  an  entire  year  was  equivalent  to  but 
3  inches  of  rain.17 

Whether  from  drift  or  from  local  precipitation,  the  effect 
of  snow  in  nourishing  the  shelf  ice  is  much  the  same,  and  it 
is  estimated  that  on  the  average  about  one  foot  of  heavy 
snow  is  each  year  added  to  the  surface  of  the  Ross  Barrier. 
If  the  contribution  of  the  ice  from  the  Beardmore  outlet  be 


224        CHARACTERISTICS  OF  EXISTING  GLACIERS 

estimated  to  have  moved  toward  the  barrier  edge  at  the 
uniform  rate  of  about  one-third  mile  annually,  before  it 
could  have  covered  the  300  miles  separating  the  outlet  from 
the  present  margin,  some  900  years  must  have  elapsed, 
and  during  this  time  this  glacier  ice  will  have  been  buried 
beneath  some  900  feet  of  compact  snow  as  measured 
at  surface  density.18  The  true  glacier  ice  derived  from  the 
outlets  is,  therefore,  not  to  be  looked  for  in  the  shelf  ice  ex- 
cept in  the  submerged  portions  where  direct  observation  has 
not  yet  gone.  The  upper  and  visible  portion  of  the  Ross 
Barrier  is  hence  in  all  probability  throughout  of  local  deri- 
vation and  is  properly  regarded  as  neve  snow.19  Some 
confirmation  of  these  conclusions  is  derived  from  the  study 
of  the  structure  of  Antarctic  icebergs,  which  after  partial 
melting,  or  after  overturning,  bring  the  bottom  layers  to 
the  light  of  day  (see  below  under  Icebergs). 

The  "  Higher  "  and  "  Lower  "  Ice  Terraces  off  King  Oscar 
Land.  —  The  Swedish  Antarctic  expedition  of  1902  en- 
countered large  areas  of  shelf-ice  in  most  respects  resembling 
that  of  the  Ross  Barrier.  This  was  met  on  the  long  sledge 
journey  of  Nordenskiold  and  Sobral  in  a  direction  west- 
southwest  ward  from  the  winter  quarters  at  Snow  Hill  Island. 
After  eight  days  upon  the  sea-ice  of  Larsen  Bay  and  when 
near  the  Seal  Islands  (see  Fig.  117),20  a  high  ice  wall  suddenly 
appeared  across  their  path.  This  wall  was  ascended  over 
the  sloping  surface  of  a  snow  drift  banked  against  it,  and  the 
course  was  laid  over  "  an  even  plateau  destitute  of  fissures." 
Once  only,  a  faint  depression  was  noted  from  which  the  land 
could  not  be  seen.  Near  the  marginal  cliff  of  this  "  lower  " 
terrace  a  few  lava  islands  projected  through  its  surface,  and 
here  alone  smooth  ice  cracks  or  pressure  ridges  were  en- 
countered. After  travelling  about  100  miles  over  the  sur- 
face of  this  "  lower  "  terrace,  the  land  was  approached, 
and  for  the  first  time,  the  surface  appeared  broken  by  numer- 


THE  MARGINAL  SHELF-ICE 


225 


ous  crevasses  so  deep  and  broad  as  effectually  to  block  further 
passage  in  that  direction.21  Here  there  rose  a  second  terrace 
of  ice  going  out  from  the  shore  of  King  Oscar  Land  and 
extending  in  a  nearly  straight  line  toward  the  east  until  it 


FIG.  117.  —  Map  showing  the  "  higher  "  and  "  lower  "  terraces  of  shelf-ice  near  King 
Oscar  Land  (after  Nordenskj  old) . 

was  lost  in  the  horizon.  In  contrast  with  the  "  lower  " 
terrace  this  "  higher  "  terrace  was  broken  into  numberless 
fissures.22  Nordenskj  old's  belief  is  that  the  shelf-ice  (the 
"  lower  "  terrace)  is  in  the  main  nourished  through  the 
precipitation  and  gradual  accumulation  of  snow  upon  the 
surface  of  sea-ice  above  a  shallow  sea.  Over  the  ice  of  Larsen 
Bay  the  sledging  party  had  found  in  October  a  thick  layer 
of  snow  covered  by  a  light  crust,  through  which  the  ice-axe 


226         CHARACTERISTICS  OF  EXISTING  GLACIERS 

could  be  driven  to  the  depth  of  a  metre.  As  the  snow  layer 
upon  the  ice  deepens,  and  the  underlying  sea-ice  is  by  its 
weight  more  and  more  depressed  toward  the  shallow  bottom, 
the  warming  effect  of  the  water  would  gradually  decrease, 
and  the  snow  layer  in  consequence  would  increase  in  thick- 
ness at  an  accelerated  rate.23 

It  is  strongly  emphasized  by  Nordenskjold  that  in  this 
accumulation  of  the  snow  the  wind  plays  a  larger  role  than 
local  precipitation.  On  the  Snow  Hill  Island  ice-foot  the 
surface  was  raised  a  few  centimetres  only  during  the  winter, 
whereas  it  increased  fully  thirty  centimetres  during  the 
summer.  It  should  be  borne  in  mind  that  the  summer 
months  have  air  temperatures  corresponding  to  those  of 
winter  in  lower  latitudes  (about  1°  F.  in  the  warmest  month), 
and  more  snow  is  precipitated  during  the  summer  months. 
This  snow  is,  moreover,  softer,  and  adheres  more  readily  to 
the  surface  on  which  it  is  deposited.  Still  further,  the  winds 
during  the  summer  months  are  upon  the  average  only  about 
half  as  strong  as  during  the  winter.  Wherever  protected 
from  the  wind  snow  accumulates,  so  that  small  islands  are 
covered,  and  the  ice-foot  glacier  pushes  out  from  the  margins 
to  be  extended  in  the  form  of  shelf-ice. 

Valuable  data  bearing  upon  this  point  are  also  being 
supplied  from  a  different  quarter.  Mr.  J.  B.  Tyrrell  during 
many  winters  spent  about  the  fresh  water  lakes  of  Canada, 
has  found  that  if  snow  falls  to  a  considerable  depth  soon  after 
the  ice  has  first  formed,  this  load  will  press  the  ice  down 
into  the  water.  Young  and  flexible  ice  will  bear  up  less 
than  its  own  thickness  of  the  dense  snow  of  the  Canadian 
wastes.  With  the  greater  thicknesses  which  are  common, 
the  ice  is  bent  down  and  water  rises  through  fissures  so  as 
to  wet  the  lower  snow  layers.  With  severe  weather  this 
wet  snow  is  frozen  and  the  ice  thickened  from  the  upper 
surface.24 


THE   MARGINAL   SHELF-ICE  227 

We  have  seen  that  the  Scott,  Shackelton,  and  Nordenskjold 
expeditions  are  practically  in  agreement  as  to  the  importance 
of  local  snow  deposition  in  the  alimentation  of  shelf  ice 
formations.  Nordenskjold  would  ascribe  both  the  origin 
and  growth  of  the  shelf  ice  of  West  Antarctica  to  this  cause, 
whereas  Scott  regards  the  Ross  Barrier  as  the  relic  of  a  much 
larger  area  of  ice  shelf  which  once  filled  all  of  Ross  Sea  and 
rested  throughout  upon  its  floor.  This  view  of  the  former 
extension  of  the  Ross  Barrier  is,  as  we  shall  see,  abundantly 
supported  by  evidence.  Of  great  importance  is  the  com- 
parison of  the  barrier  margins  of  1840  and  of  1902  (see  Fig. 
113),  since  during  a  period  of  sixty  years  this  wall  has  retired 
in  places  from  twenty  to  thirty  miles. 

The  "  West-ice  "  of  Kaiser  Wilhelm  Land.  —To  the  west 
of  Posadowsky  Bay  and  westward  and  northward  from  the 
inland  ice  of  Kaiser  Wilhelm  Land,  lies  a  dead  mass  of  ice 
which  the  late  Professor  Philippi  regarded  as  true  shelf-ice, 
and  which  in  the  main  may  be  compared  to  that  of  the  Ross 
Barrier.25  Owing,  however,  to  the  different  opinions  which 
have  been  expressed  concerning  its  origin,  this  area  of  stag- 
nant ice  has  been  given  the  colorless  designation  "  West- 
ice."  Unlike  the  Ross  Barrier,  with  which  the  West-ice 
has  been  compared,  it  has  a  blue  color,  and  as  already  men- 
tioned, it  appears  to  be  stagnant,  since  no  evidences  of  dis- 
turbance have  been  found  at  either  its  sea  or  its  inland-ice 
margins.  Unlike  the  Ross  Barrier,  also,  it  lacks  the  smooth 
surface  of  that  body,  where  it  has  been  explored.  For  the 
most  part,  its  surface  is  very  uneven,  and  might  even  be 
described  in  places  as  chaotic  or  labyrinthine.  In  its 
northeastern  portion  it  is  traversed  by  deep  rift-like  valleys, 
which  led  von  Drygalski  to  believe  that  it  is  constituted  of  a 
group  of  closely  crowded  icebergs  more  or  less  welded  to- 
gether and  with  the  intervening  passages  partially  healed  by 
the  indrifted  snow.  He  has,  however,  referred  to  the  West- 


228         CHARACTERISTICS  OF  EXISTING  GLACIERS 

ice  as  similar  to  the  shelf  ice  of  Ross  Sound  and  West  Ant- 
arctica.26 

Seen  from  the  sea  when  the  "  Gauss  "  skirted  its  front,  the 
West-ice  showed  a  high  perpendicular  wall  in  all  respects 


FIG.  118. — West-ice  seen  from  the  "Gauss"  off  Kaiser  Wilhelm  Land  (after  von 

Drygalski) . 

resembling  the  cliff  faces  of  the  other  bodies  of  Antarctic 
shelf  ice  (see  Fig.  118),  and  this  wall  was  followed  through 
three  degrees  of  longitude.  The  eastern  portion  of  the  mass, 
which  was  examined  by  sledging  parties,  pushes  its  margin 
out  to  the  northward  and  ends  in  three  great  ice  tongues 
separated  by  bays  and  terminating  in  steep  cliffs.  These 


FIG.  119.  —  The  junction  of  the  West-ice  and  the  sea  ice  (after  von  Drygalski). 

cliffs  at  the  different  localities  that  were  visited  varied  in 
height  from  fifteen  to  sixty-five  feet.  Locally  drifts  of  snow 
formed  sloping  bridges  down  to  the  sea  ice  (see  Fig.  119). 
Both  sea  and  shelf  ice  rose  and  fell  together  with  the  tides, 
since  no  tide  cracks  were  observed  to  separate  them.  This 
indication  that  the  West-ice  is  afloat  was  confirmed  through 


THE  MARGINAL  SHELF-ICE  229 

the  absence  of  any  ice-foot,  as  well  as  by  soundings,  which 
showed  a  depth  of  water  along  its  borders  of  six  hundred 
metres.  Deep  disintegration  of  the  West-ice  through 
melting  upon  its  upper  surface  was  everywhere  apparent. 
Old  cracks  running  parallel  to  its  margin  were  melted  on 
one  side,  so  that  steep  cliffs  faced  northward  and  formed  the 
south  wall  of  channels  for  surface  streams.  Broad  trough- 
like  inbreaks  led  into  the  mass  from  its  eastern  margin, 
and  on  one  of  these  the  floor  had  sunk  unequally  so  as  to 
leave  the  north  side  high  and  the  south  side  at  a  far  lower 
level. 

In  general,  however,  the  surface  of  the  West-ice  is  flat 
with  no  apparent  increase  of  elevation  toward  the  west  and 
south,  though  far  in  the  distance  along  these  directions  were 
seen  the  rising  slopes  of  the  inland-ice.  That  there  is  to-day 
no  functional  connection  between  the  West-ice  and  the 
inland-ice  has  been  asserted  by  von  Drygalski  (see  below, 
p.  250). 

According  to  von  Drygalski,  the  West-ice  is  kept  in  place 
because  of  the  shallowness  of  Posadowsky  Bay,  icebergs  being 
first  stranded  on  the  shallows  and  the  intervening  lanes 
being  thereafter  filled  in  by  drifted  snow.  While  this  process 
furnishes  an  explanation  for  the  southern  or  older  sections 
of  the  mass,  the  northern  or  newer  portions  he  believes  to 
have  been  formed  by  the  thickening  of  sea  ice  which  has 
remained  in  place  for  a  number  of  seasons.  Three  north 
and  south  bands  are  made  out  whose  order  from  east  to 
west  appears  to  be  significant  in  showing  the  manner  of 
formation  of  the  greater  portion  of  the  West-ice  mass. 
The  zone  to  the  eastward  and  on  the  margin  is  pack-ice 
(Scholkneis)',  the  middle  zone  is  largely  berg  ice  frozen 
into  a  continuous  sheet;  while  to  the  west  the  intervening 
spaces  which  separate  similar  fleets  of  bergs  have  become 
either  partially  or  wholly  filled  in  by  drift  snow,  the  product 


230        CHARACTERISTICS  OF  EXISTING  GLACIERS 

being  called  " full-ice  "  (Votteis),  or,  in  other  words,  the  West- 
ice  proper  27  (see  Fig.  120). 


Ice 


Ice 


FIG.  120.  —  Diagram  showing  manner  of  formation  of  West-ice.  Eroded  icebergs 
crowded  together,  cemented  by  pack-ice  and  the  intervening  lanes  partly  filled 
in  with  snow  (after  v.  Drygalski). 

The  Shelf -ice  Tongues  of  Victoria  Land.  —  Victoria  Land 
has  furnished  several  examples  of  a  new  type  of  glacier  ice 


FIG.  121.  —  Map  of  the  glaciers  and  ice  barrier  tongues  about  the  head  of  Robert- 
son Bay,  Victoria  Land  (after  Borchgrevink) . 


THE  MARGINAL  SHELF-ICE  231 

which  has  interesting  relationships  to  the  shelf-ice  of  the 
Antarctic  regions.  It  is  deserving  of  a  distinct  name,  and 
the  term  shelf-ice  tongue  (ice  barrier  tongue  of  the  Shack- 
leton  expedition)  seems  on  the  whole  the  most  characteristic 
and  descriptive.  A  related  form  of  tongue  was  first  described 
by  Borchgrevink  in  his  map  of  the  Sir  John  Murray  glacier 
on  Robertson  Bay,  which  lies  behind  Cape  Adare  in  Victoria 
Land  (see  Fig.  121).  This  glacier  with  the  Dugdale  glacier 
descends  to  the  sea  below  Geikie  Land,  where  it  is  for  some 
distance  wedged  in  between  Duke  of  York  Island  and  the 
shore.  It  pushes  out  to  sea  in  the  form  of  a  long  dock, 
which  is  80  feet  in  height  near  its  margins  and  rises  into  the 
form  of  one  of  the  dry  deltas  of  an  arid  region.  This  form 
of  its  surface  is  of  special  interest  in  showing  clearly  the 
connection  as  regards  nourishment  between  the  ice  of  the 
tongue  and  the  glacier  outlet  above.  From  the  peculiarities 
of  its  surface  it  would  appear  to  include  no  true  shelf-ice 
such  as  is  found  in  the  Ross  Barrier. 

Three  large  and  well  marked  examples  of  shelf-ice  tongue 
or  "  piedmonts  afloat "  have  been  reported  on  by  the 
Shackleton  expedition.  These  are  Glacier  Tongue,  about 
five  miles  long  and  located  near  the  winter  quarters  on 
McMurdo  Sound,  and  the  much  larger  Nordenskiold  and 
Drygalski  shelf-ice  tongues  on  the  shore  of  Victoria  Land 
to  the  west  of  Ross  Sea  (see  Fig.  122).  Smaller  tongues  of 
the  same  type,  Harbor  and  Cheetham  shelf-ice  tongues,  lie 
similarly  at  the  foot  of  other  but  smaller  glaciers  upon  the 
same  shore.  Both  the  Glacier  Tongue  on  McMurdo  Sound 
and  the  Drygalski  tongue  to  the  northward  were  shown  by 
soundings  near  their  outer  margins  to  be  afloat.  The  Dry- 
galski tongue  pushes  out  some  thirty  miles  from  the  shore 
and  is  more  than  twelve  miles  in  width.  On  the  basis  of 
soundings  it  has  been  thought  to  be  afloat  for  at  least  three- 
fourths  of  its  length,  but  inasmuch  as  it  rises  toward  the 


E. Longitude 


Fig.  122.  —  Map  showing  the  shelf-ice  tongues  on  the  west  of  Ross  Sea  with  the 
glacier  outlets  which  descend  to  them  from  Victoria  Land  (after  Shackleton). 

232 


THE  MARGINAL  SHELF-ICE  233 

centre  to  heights  much  above  its  edge,  this  may  be  true  for 
the  marginal  portions  only.28 

The  Drygalski  ice  barrier  tongue  is  clearly  nourished  from 
the  ice  plateau  through  the  great  David  Outlet,  the  ice  of 
which  raises  its  shoreward  end  into  a  steep  and  irregular 
ice  apron;  but  farther  out  this  is  "  levelled  up  with  snow  " 
and  passes  into  the  true  flat  shelf-ice.  At  a  point  only 
eighteen  miles  from  the  shore  the  marginal  cliff  was  about 
fifty  feet  above  the  water.  In  all  essential  respects  this 
tongue  appears  to  resemble  that  portion  of  the  Ross  Barrier 
which  is  just  below  the  Beardmore  Outlet  (see  Fig.  134,  p. 
258),  with  the  exception  that  the  broad  extension  of  shelf-ice 
is  here  reduced  to  a  small  marginal  rim  (in  the  tongue  of  the 
Sir  John  Murray  Glacier  there  is  no  rim  whatever).  As  there 
is  every  indication  that  the  Drygalski  tongue  is  in  motion 


FIG.  123.  —  Ideal  section  through  shelf-ice  tongue  showing  the  apron-like  foot 
of  the  outlet  which  feeds  it,  and  the  probable  pedestal  by  which  it  is  connected 
with  the  bottom  and  maintained  in  position.  The  relation  of  its  glacier  ice  to 
the  n6v6  of  local  derivation  is  also  indicated. 

and  receiving  abundant  nourishment  from  the  David  Outlet, 
though  levelled  up  with  snow  near  its  outer  edge,  additional 
light  is  thrown  upon  the  origin  of  shelf-ice  in  general.  The 
probable  section  of  a  shelf -ice  tongue  is  represented  sche- 


234         CHARACTERISTICS  OF  EXISTING  GLACIERS 

matically  in  Fig.  123.  The  nourishing  glacier  raises  the 
surface  of  the  tongue  into  an  apron,  and  in  consequence 
depresses  the  bottom  of  the  submerged  portion,  and  being 
nearest  the  shore  where  the  water  is  shallowest,  must  develop 
a  sort  of  ice  pedestal  whose  effect  will  be  to  stiffen  the 
structure  and  prevent  its  being  shifted  in  position.  The 
attenuated  form  which  some  of  the  tongues  maintain  it 
would  otherwise  be  difficult  to  explain. 

The  Nordenskjold  ice  barrier  tongue  is  somewhat  smaller 
than  the  Drygalski  tongue  and  appears  to  be  no  longer  deriv- 
ing nourishment  from  the  plateau  ice  above.  It  is  thus  a 
relic  only  of  the  once  larger  Ross  Barrier,  and  has  additional 
interest  because  its  southern  edge  is  formed  of  ice  probably 
originally  derived  from  the  Mawson  Outlet,  whereas  its 
northern  edge  is  of  snow  forty  to  fifty  feet  in  thickness 
brought  by  the  southerly  blizzards  from  the  southern  side. 
This  is  bounded  by  vertical  sea  cliffs  where  slices  have  been 
carried  away  with  the  sea-ice  during  the  summer.  It  thus 
emphasizes  the  important  role  which  wind  drift  plays  in  the 
formation  of  shelf-ice. 

On  a  portion  of  the  earth's  surface  where  rain  is  unknown, 
and  where  the  air  temperatures  seldom  rise  above  the  freez- 
ing-point, unfrozen  water  as  a  geological  agent  has  an  almost 
negligible  importance.  In  certain  localities,  however,  where 
the  foehn  winds  are  especially  strong,  such,  for  example,  as 
the  David  Outlet,  its  importance  may  be  considerable. 
During  the  weeks  of  December  and  January  torrents  of  water 
rush  off  the  surface  of  the  Drygalski  tongue  in  the  form  of 
englacial  and  subglacial  streams.  These  either  cut  deep 
open  valleys  upon  the  surface,  or  tunnel  channels  under  the 
hard  snow  and  ice. 

The  Rectangular  Table  Berg  of  Antarctic  Waters.  —  The 
normal  iceberg  of  Antarctic  seas  is  as  different  as  possible 
from  the  Arctic  type,  and  for  reasons  which  are  now  suffi- 


THE  MARGINAL  SHELF-ICE 


235 


ciently  obvious.  In  Greenland,  true  glacier  ice  descends  to 
the  fjord  heads,  and  there  gives  birth  to  bergs  of  blue  ice 
which  are  limited  in  size  both  by  the  size  of  the  fjord  and  by 
the  crevasses  upon  the  ice.  In  the  Antarctic,  so  far  as  yet 
known,  glacier  ice  descends  directly  to  the  open  sea  at  few 
points  only,  but  in  its  place  appears  the  shelf-ice,  and  tabular 
bergs  separate  along  broad  sea  fronts  which  are  measured 
sometimes  in  the  hundreds  of  miles  (see  Fig.  124).  The 
size  of  Antarctic  bergs  is  in  consequence  many  times  greater, 


FIG.  124.  —  The  Ross  Barrier  breaking  away  to  form  a  tabular  and  rectangular 
iceberg  (after  Shackleton). 

and  their  form  is  tabular29  like  the  ice-shelf  from  which  they 
have  been  born  (see  Fig.  125). 30 

Most  of  the  bergs  which  were  seen  in  Ross  Sea  had  been 
derived  from  the  Ross  Barrier.  They  separate  from  it  in 
great  rectangular  blocks  and  leave  a  relatively  smooth  ver- 
tical face,  which  later  under  the  action  of  the  waves  becomes 
undercut  and  more  irregular  through  the  separation  of  small 
bergs  on  rectangular  joint  planes.  It  is  thus  easy  to  deter- 
mine those  parts  of  the  barrier  edge  which  are  relatively 
fresh,  and  those  which  have  not  for  a  considerable  time 
given  birth  to  a  tabular  berg  (see  plate  31,  A  and  B).31 


236 


CHARACTERISTICS  OF  EXISTING  GLACIERS 


Such  bergs  often  show  in  addition  a  distinctly  terraced  struc- 
ture (see  Fig.  126).  The  term  tabular  berg,  which  is  in  com- 
mon use,  is,  however,  particularly  well  chosen,  because  it 


i'lo.   125.  —  Rectangular  and  tabular  iceberg  of  Antarctic  waters   (after  Wyville 

Thomson). 

describes,  not  alone  the  smooth  horizontal  upper  surface, 
but  the  well-squared  rectangular  outlines  in  the  plan.  Too 
little  attention  seems  to  have  been  directed  to  this  impor- 
tant fact,  to  which  practically  all  photographs  of  Southern 
icebergs  bear  witness.  It  indicates,  as  we  believe,  that  the 
shelf-ice  at  least  near  its  margins  is,  particularly  near  the 


FIG.  126.  —  Tabular  Antarctic  iceberg  showing  perpendicular  and  rectangular  joint- 
ing (after  Wyville  Thomson). 

top,  generally  intersected  by  vertical  joints  after  the  manner 
of  horizontal  bedded  and  compact  rocks  (see  Figs.  126  and 
127).32  Such  joints  appear  indeed  in  many  views  and  might 
perhaps  be  explained  in  part  by  the  torsional  strains  set  up 
by  the  tidal  movements  —  not  unlike  those  described  in  the 
well-known  experiments  of  Daubree.33  References  to  this 
jointed  structure  are,  however,  seldom  met  with  in  the  liter- 


THE  MARGINAL  SHELF-ICE 


237 


ature,  but  those  of  the  "  Challenger  "  reports  are  sufficiently 
clear:34— 


FIG.  127.  —  View  of  a  tilted  tabular  iceberg  showing  the  rectangular  lines  of  the 
plan  (after  Wyville  Thomson). 

Nearly  all  of  the  flat-topped  bergs  showed  numerous  crevasses 
in  their  cliffs  near  their  summits,  and  these  were  always  widest 
towards  their  summits,  and  were  irregularly  perpendicular  in  gen- 
eral direction. 


The  stratified  structure  of  the  bergs  is  best  seen  in  the  case  of 
the  flat-topped  rectangular  bergs,  where  an  opportunity  is  afforded 
of  examining  at  a  corner  two  vertical  cliff  faces  meeting  one  an- 
other at  a  right  angle. 


Cliff  surfaces,  where  freshly  fractured,  showed  an  irregular 
jointing  and  cleavage  of  the  entire  mass,  very  like  that  shown  in 
a  cliff  of  compact  limestone. 

Gourdon  of  the  late  French  expeditions  to  the  Antarctic 
refers  to  such  bergs  as  "  absolutely  prismatic  at  their  birth."35 

Descriptions  of  the  structure  of  Southern  icebergs  have 
much  in  common  with  those  of  the  Ross  Barrier,  save  only 
that  they  reveal  near  the  bottom  especially  the  presence  of 
blue  ice  layers  intercalated  in  the  white. 


238         CHARACTERISTICS  OF  EXISTING  GLACIERS 

According  to  Arctowski  the  tabular  icebergs  which  he  saw 
to  the  west  of  West  Antarctica  are  neve  near  the  top,  while 
the  alternate  blue  and  white  bands  appear  only  near  the 
base.  Both  these  latter  have  the  granular  structure  of  neve 
ice.36 

Wilkes  reported  icebergs  which  were  from  fifty  to  two  hun- 
dred and  fifty  feet  in  height  with  definite  strata,  of  which 
thirty  were  counted  in  the  smaller  bergs  and  eighty  in  some 
of  the  largest,  the  average  thickness  of  the  layers  being  about 
two  feet.37  Wyville  Thomson  says  of  such  bergs  that  "  the 
entire  mass  shows  a  well  marked  stratification,  being  com- 
posed of  alternate  layers  of  white,  opaque-looking,  and  blue, 
more  compact  and  transparent  ice." 

Towards  the  lower  part  of  the  cliffs,  the  strata  are  seen  to  be 
extremely  fine  and  closely  pressed,  whilst  they  are  thicker,  with 
the  blue  lines  wider  apart  in  proportion  as  they  are  traced 
toward  the  summits  of  the  cliff.  In  the  lower  regions  of  the 
cliffs  the  strata  are  remarkably  even  and  horizontal,  whilst 
toward  the  summit,  where  not  subjected  to  pressure,  slight 
curvings  are  to  be  seen  in  them  corresponding  to  the  inequalities 
of  the  surface  and  the  drifting  of  the  snow.38 

This  presence  of  blue  layers  was  not,  however,  observed 
in  the  icebergs  near  the  great  barrier  itself.39  This,  as  well 
as  a  thorough  study  of  the  barrier  edge,  makes  it  probable 
that  the  icebergs  studied  by  Wilkes  and  Thomson  outside 
the  Arctic  Circle  were  derived  from  some  other  masses 
of  Antarctic  shelf-ice,  which  on  the  basis  of  their  observa- 
tions must  contain  blue  ice  layers.  The  definite  separation 
of  the  bergs  into  thick  white  layers  near  the  top  with  thin 
intermediate  blue  layers  only,  and  the  concentration  of  the 
latter  toward  the  bottom,  where  pressure  has  removed  the 
air  from  the  more  porous  white  layers,  gives  the  strongest 
confirmation  to  the  views  of  Reid  and  Hess  40  based  upon 


THE  MARGINAL  SHELF-ICE  239 

observations  on  mountain  glaciers,  that  the  blue  veins  sepa- 
rate the  annual  snow  deposits  of  the  neve. 

Speaking  of  the  stratification  in  Southern  icebergs,  von 
Drygalski  says: 

Without  doubt  it  is  similar  to  original  neve  stratification,  only 
that  this  in  the  South  occurs  down  to  the  sea  level,  because  no 
separation  exists  between  regions  of  alimentation  and  removal. 
The  clear  layers  are  those  which  for  a  long  time  (not  necessarily 
annual  periods)  have  lain  on  the  surface  without  new  piling  up  of 
the  snow.  They  are  either  melted  by  the  sun's  rays,  and  thus 
hardened,  or  subjected  to  pressure  and  rendered  firmer  by  the 
wind.  Between  them  there  are  more  porous  layers  which  appear 
as  the  white  ones  in  the  stratification  and  are  characterized  by  a 
greater  content  of  air.41 

To  test  the  different  properties  of  the  white  and  blue  por- 
tions of  a  berg,  two  twelve-pound  shots  were  fired  from  the 
"  Challenger/7  one  at  the  blue  lower  layers,  and  the  other 
at  the  white  upper  zone.  The  first  splintered  the  relatively 
hard  and  brittle  blue  ice,  leaving  conchoidal  surfaces,  while 
the  second  buried  itself  in  the  white  porous  mass.42  Frag- 
ments of  the  white  layer  were  taken  aboard  the  "  Challenger  " 
and  being  subjected  to  pressure,  were  found  to  be  easily 
deformed,  whereas  the  blue  ice,  under  similar  treatment, 
did  not  yield.43 

Southern  icebergs  of  a  different  type  are  also  formed  where 
the  inland-ice  comes  directly  to  the  sea,  with  no  intermediate 
barrier  of  shelf-ice,  as  is  the  case  in  Kaiser  Wilhelm  Land. 
The  Ross  Barrier  is  not  only  much  the  largest  well  known 
mass  of  shelf-ice,  but  its  edge  is  more  than  ten  degrees  nearer 
the  pole  than  those  other  barriers  which  have  been  merely 
sighted  by  navigators.  It  seems  certain  that  the  land  of 
Wilkes  Land  is  relatively  near  the  barrier  edge,  and  this,  as 
well  as  the  climatic  differences,  might  perhaps  account  for 
the  differences  between  the  icebergs  examined  by  Wilkes  and 


240         CHARACTERISTICS  OF  EXISTING  GLACIERS 

Wyville  Thomson,  and  those  which  were  seen  in  Ross  Sea 
and  examined  by  the  recent  British  expeditions.  With  a 
narrower  barrier,  the  local  neve  of  the  shelf-ice  would  be 
relatively  thin,  so  that  the  glacier  ice  with  its  blue  layers 
should  be  nearer  the  surface.  The  studies  of  Hess  appear  to 
indicate  that  a  differential  motion  between  successive  layers 
of  neve  may  account  for  the  development  of  the  blue  layers 
on  these  planes.44  There  is  much  need  of  study  of  the  ice 
masses  in  Wilkes  Land  in  order  to  clear  up  the  relationships 
of  the  bergs  encountered  in  neighboring  seas. 

The  drift  of  the  bergs  which  are  born  of  the  Ross  Barrier 
is  to  the  northward,  and  after  passing  Cape  Adare,  to  the 
westward.45  The  icebergs  derived  from  the  barriers  of  Wilkes 
Land  are  borne  to  the  westward  and  the  northward.  When 
they  have  passed  the  parallel  of  65°  S.  they  enter  the  warm 
surface  layers  of  sea  water  and  are,  in  consequence,  more 
rapidly  melted  in  the  water,  at  the  same  time  that  the 
warmer  air  temperatures  reduce  their  exposed  surfaces,  trans- 
forming them  into  fantastic  groups  of  towers  and  minarets.46 

The  surpassing  beauty  of  these  partially  melted  icebergs 
has  been  described  in  picturesque  language  by  Gourdon.47 

Thus  in  place  of  the  great  regular  and  prismatic  tabular  bergs 
are  formed  those  bizarre  and  complicated  monuments,  which  recall 
the  ice  bergs  of  the  North :  towers,  pyramids,  bell-towers,  cathe- 
drals, or  palaces,  Gothic  spires,  or  Roman  porticoes,  all  styles  meet, 
all  architectures  touch  elbows;  for  these  are  forms  more  strange 
and  unexpected  than  the  most  capricious  imagination  could  have 
dreamed.  The  whole  gamut  of  blues  and  greens  plays  over  the 
walls  of  these  edifices  or  within  the  channelings  which  course  about 
them,  and  the  whiteness  of  the  purest  marble  does  not  equal  theirs. 
The  transparency  of  the  water  permits  of  following  the  fairy  land 
of  their  azure  grottoes  far  below  the  surface  of  the  sea.  During 
the  summer,  little  cascades  fall  over  their  sides,  mingling  their  waters 
with  the  waves  which  break  against  their  glistening  flanks ;  stalac- 
tites hang  from  cornices  and  capitals. 


THE  MARGINAL  SHELF-ICE  241 

Under  the  rays  of  the  sun  the  ice  sparkles  with  the  fire  of 
jewels ;  their  silhouettes  take  on  life  in  an  atmosphere  of  extraor- 
dinary transparency ;  the  warmest  colorations  invade  the  sky  and 
are  reflected  upon  the  sea,  and  there  are  enchanting  tableaux 
which  are  offered  to  the  eye. 

When,  however,  the  sun  disappears  from  the  scene,  it  is  a  land 
of  death  which  is  presented  by  these  mountains  of  ice.  Soon 
gathered  in  great  numbers,  they  resemble  the  fantastic  ruins  of  a 
gigantic  marble  city ;  in  a  little  while  and  once  isolated,  they  pass, 
white  phantoms,  majestic  and  silent,  into  the  mystery  of  the  oolar 
mist. 

Often  before  this  stage  has  been  reached,  they  have  been 
deeply  tunnelled  in  sea  arches,  have  been  melted  unequally, 
and  have  lost  some  of  their  stability  so  as  to  become  tilted 
(see  Fig.  127,  p.  237),  or  even  overturned.48  Sir  John  Murray, 
who  in  the  "  Challenger  "  had  such  excellent  opportunity 
to  study  floating  ice,  has  said  of  the  melted  bergs:49  — 

Waves  dash  against  the  vertical  faces  of  the  floating  ice- 
islands  as  against  a  rocky  shore,  so  that  at  the  sea  level  they  are 
first  cut  into  ledges  and  gulleys,  and  then  into  caves  and  caverns 
of  the  most  heavenly  blue  from  out  of  which  there  comes  the  re- 
sounding roar  of  the  ocean,  and  into  which  the  snow-white  and 
other  petrels  may  be  seen  to  wing  their  way  through  guards  of 
soldierlike  penguins  stationed  at  the  entrances.  As  these  ice- 
islands  are  slowly  drifted  by  wind  and  current  to  the  north,  they 
tilt,  turn,  and  sometimes  capsize,  and  then  submerged  prongs 
and  spits  are  thrown  high  into  the  air,  producing  irregular  pin- 
nacled bergs  higher,  possibly,  than  the  original  table-shaped  mass. 

Before  reaching  the  40th  parallel  of  south  latitude,  the 
bergs  are  entirely  dissolved.  The  tilting  and  overturning 
which  they  first  undergo,  permits  of  an  examination  of  their 
under  surfaces,  and  it  does  not  appear  that  any  glacier  worn 
rock  debris  has  been  observed  in  them.  The  debris  of  this 
nature  observed  in  the  bottom  of  the  blue  icebergs  described 
by  von  Drygalski  and  Philippi  in  Posadowsky  Bay,  which 


242         CHARACTERISTICS  OF  EXISTING  GLACIERS 

are  of  different  origin  and  derived  from  the  true  inland-ice, 
will  be  discussed  under  another  section.  The  fact  of  impor- 
tance is  that  the  white  tabular  bergs  have  not  as  yet  revealed 
such  materials. 

REFERENCES 

1  O.  Nordenskiold,  "  Einge  Beobachtungen  iiber  Eisformen  und  Ver- 
gletscherung    der    antarktischen    Gebiete,"    Zeit.    f.   Gletscherk.,   vol.    3, 
1909,  p.  322. 

2  H.  T.  Ferrar,  in  Scott's  "  Voyage  of  the  '  Discovery,'  "  vol.  2,  pp.  461-2. 
3Wilkes,  "Narrative  U.  S.  Exploring  Expedition,  1838-1842,"  vol.  2, 

pp.  350,  365. 

4  Brown,  et  al.,  "The  Voyage  of  the  '  Scotia,'  being  the  record  of  a  voy- 
age of  exploration  in  Antarctic  seas,  by  three  of  the  staff."    Edinburgh  and 
London,  1906,  p.  236. 

5  Borchgrevink,  I.e.,  final  map. 

6  Scott,  "Voyage  of  the  'Discovery,'"  vol.  1,  pp.  163-204,  map  at  end 
of  volume. 

7  The  Royal  Society,  National  Antarctic  Expedition,  1901-1904,  Album 
of  photographs  and  sketches,  London,  1906. 

8T.  W.  E.  David   and    R.  E.  Priestley,  in  App.  II  of   Shackelton's- 
"Heart  of  the  Antarctic,"  vol.  2,  p.  288. 
9  David  and  Priestley,  I.e. 

10  Quoted  by  Murray,  Smithsonian  Report  for  1893,  1894,  p.  358 ;   also 
ibid.,  for  1897,  1898,  p.  415. 

11  Scott,  I.e.,  vol.  2,  p.  418. 

12  Scott,  I.e.,  vol.  2,  p.  420. 

13  Scott,  I.e.,  vol.  2,  p.  419.     David  and  Priestley,  I.e.,  p.  289. 

14  Shackelton,  I.e.,  vol.  2,  pp.  12-13.     Cf.  the  moats  about  nunataks 
(ante  p.  169  and  post  p.  257). 

15  E.  von  Drygalski,  "  Die  Bewegung  des  antarktisches  Inlandeises," 
Zeit.  f.  Gletscherk.,  vol.  1,  1906-7,  pp.  61-65. 

16  David  and  Priestley,  I.e.,  p.  287. 

17  Bernacchi,  I.e.,  p.  308. 

18  It  should  be  stated  that  Mr.  Bernacchi,  an  officer  of  the  Scott  expedi- 
tion, does  not  accept  the  view  that  the  Ross  Barrier  is  floating  except  in 
the  vicinity  of  its  margin,  and,  moreover,  regards  it  as  fed  in  the  usual 
manner  of  glaciers  —  by  material  which  moves  down  from  the   higher 
levels  along  the   southern  and  western  margin    (Geographical  Journal, 
vol.  25,  1905,  p.  384).     Gannett,  also,  has  taken  strong  exception  to  the 
view  of  partial  surface  alimentation  as  above  expressed  and  as  advocated 
by  Scott,  Shackelton,  and  David  (Nat.  Geogr.  Mag.,   vol.  21,  1910,  pp. 
173-174). 

19  David  and  Priestley,  I.e.,  p.  287. 

20  Otto  Nordenskiold  and  J.  Gunnar  Andersson,  "Antarctica,  or  Two 
Years  amongst  the  Ice  of  the  South  Pole."     London,  1905,  p.  208. 


THE  MARGINAL  SHELF-ICE  243 

21  Otto  Nordenskiold,  "  Die  Polarwelt  und  ihre  Nachbarlander,"  1909, 
pp.  82-84. 

22  Nordenskiold  and  Andersson,  "  Antarctica,"  p.  220,  and  map  opposite 
p.  316. 

23  Otto   Nordenskiold,   "  Einige  Beobachtungen,   iiber   Eisformen   und 
Vergletscherung  der  Antarktischen  Gebiete,"  Zeit.  f.  Gletscherk.,  vol.  3, 
1909,  pp.  326-329.     See,  however,  E.  Philippi,  "Ueber  die  Landeis-Beo- 
bachtungen  dej  letzen  fiinf  Siidpolar-Expeditionen,"   Zeit.  f.  Gletscherk., 
vol.  2,  1907,  pp.  1-21. 

24  J.  B.  Tyrrell,  "  Ice  on  Canadian  Lakes,"  Trans.  Can.  Inst.,  vol.  9, 1910, 
pp.  4—5  (reprint). 

25  E.  Philippi,  "  Ueber  die  Landeis-Beobachtungen  der  letzen  fiinf  Siid- 
polar-Expeditionen," Zeit.  f.  Gletscherk.,  vol.  2,  1907-1908,  pp.   9-11. 

26  E.  von  Drygalski,  "  Zum  Kontinent  des  eisigen  Siidens,  etc.,"  p.  439. 
From  this  view  Philippi  has  strongly  dissented  (Zeit.  f.   Gletscherk.,  I.e., 
p.  10). 

27  E.  v.  Drygalski,  "Das  Schelfeis  der  Antarktis  am  Gaussberg,"  Sitz- 
ungsber.  k.  bay.  Akad.  d.  Wiss.,  Math.-phys.  KL,  1910,  pp.  1-44,  pi. 

28  David  and  Priestley,  I.e.,  pp.  283-286. 

29  H.  Stille,  "  Geologische  Charakterbilder,"  heft  1,  1910,  plates  2-6. 

30  Concerning  the  ice  of  Antarctic  bergs  Wilkes  has  stated  that  those 
encountered  along  the  coast  of  Wilkes  Land  varied  from  a  quarter  of  a 
mile  to  five  miles  in  length  (I.e.,  p.  350).     Scott  has  made  mention  of  a 
berg  five  or  six  miles  in  length,  and   apparently  about  as  wide,  but  he 
states  that  he  saw  few  which  exceeded  a  mile  in  length  or  150  feet  in 
height.     The  highest  which  he  observed  was  measured  as  240  feet  (Geogr. 
Jour.,  vol.  26,  p.  356).     Some  of  the  accounts  of  bergs  of  exceptional  size 
may  perhaps  be  explained  by  the  assemblage  of  a  number  closely  crowded 
together  and  appearing  as  one.     Such  groupings  might  easily  be  mistaken 
for  shelf-ice,  and  no  doubt  in  some  cases  have  been. 

31  Scott,  vol.  2,  pp.  408-409,  pi.  opposite  p.  408. 

32  Shackelton,  vol.  2,  plate  opposite  p.  22. 

33  Geologie  Experimental,  1879,  pp.  506-515. 

34  Wyville  Thomson,  "Challenger  Report,"  Narrative,  vol.  1,  1865,  pt. 
I,  pp.  431-432,  pis.  B.  C.  D. 

35  Gourdon,  I.e.,  1908,  p.  133. 

36  H.  Arctowski,  "The  Antarctic  Voyage  of  the  'Belgica'   during  the 
years  1897,  1898,  and  1899,"  Geogr.  Jour.,  vol.  18,  1901,  p.  374.     See  also 
Pet.  Mitt.,  Erganzungsh.,  144,  1903,  pp.  15,  19,  21. 

87  Wilkes,  I.e.,  p.  253. 

38  Wyville  Thomson,  I.e.,  pp.  431-432. 

39  David  and  Priestley,  I.e.,  pp.  287-289. 

40  H.  F.  Reid,  "The  Relations  of   the  blue  veins  of  glaciers  to  their 
stratification,"  C.  R.  IXme  Congres  Geol.  Intern.,  1903,  Vienna,  pp.  703-706. 
H.  Hess,  "Die  Gletscher,"  Braunschweig,  1904,  pp.  175-178. 

41  E.  von  Drygalski,  "  Zum  Kontinent,  etc.,"  p.  455. 

42  Murray,  Smithsonian  Rept.  for  1897,  1898,  p.  419. 


244        CHARACTERISTICS  OF  EXISTING  GLACIERS 

«  Murray,  Smithson.     Rept.,  1893,  1894,  p.  363. 
44  Hess,  l.b.,  p.  177. 

46  Wilkes,  1.0.,  pp.  352-353.    Scott,  I.e.,  vol.  2,  p.  412.    Ferrar,  I.e.,  p.  463. 

46  Wilkes,  I.e.,  p.  351. 

47  Gourdon,  I.e.,  1908,  p.  134. 

48  Scott,  I.e.,  pis.  opposite  pp.  380,  382,  393,  410. 

*  'urray,  Geogr.  Jour.,  vol.  3.     Reprinted  in  Smithson.  Report  for 
p.  363. 


CHAPTER  XIV 

THE  ANTARCTIC  CONTINENTAL   GLACIER  WHERE 
UNCONFINED 

Inland-ice  Margin  on  Kaiser  Wilhelm  Land. — The  Ant- 
arctic continental  glacier,  the  great  body  of  ice  which  is 
supposed  to  occupy  the  vast  central  plateau  region  of  the 
continent,  has  been  studied  in  but  two  districts  —  Victoria 
Land  and  Kaiser  Wilhelm  Land.1  Such  ice  has  been  more 
or  less  indistinctly  seen  from  the  sea  at  a  number  of  points, 
most  recently  in  Coats  Land  on  Weddell  Sea  by  the  "  Scotia  " 
expedition.  This  view  is  thus  described : 2  - 

The  surface  of  this  great  inland  ice,  of  which  the  barrier  was 
the  terminal  face  or  sea-front,  seemed  to  rise  up  very  gradually 
in  undulating  slopes,  and  faded  away  in  height  and  distance  into 
the  sky,  though  in  one  place  there  appeared  to  be  the  outline  of 
distant  hills:  if  so,  they  were  entirely  ice-covered,  no  naked  rock 
being  visible. 

The  ice  here  reached  the  sea  in  a  narrow  barrier  with  cliff 
one  hundred  to  one  hundred  and  fifty  feet  high,  while  off  its 
edge  the  sea  was  found  to  have  a  depth  of  940  feet.3 

It  is  this  type  of  inland-ice  not  confined  by  an  encircling 
mountain  rampart  which  was  studied  within  a  very  narrow 
marginal  zone  by  the  German  Antarctic  expedition  of 
1901-1903.4 

As  seen  from  the  sea,  "  it  was  beyond  a  doubt  that  the  ice 

245 


246         CHARACTERISTICS  OF  EXISTING  GLACIERS 


all  lay  upon  land,  for  one  could  see  dark  fissures  in  its  surface 
arranged  in  different  systems.  Everywhere  this  inland- 
ice  ended  at  the  sea  in  a  steep  edge  40  to  50  metres  in  height. 
The  surfaces  behind  it  might  rise  to  300  metres,  but  soon 
graded  over  into  flat  slopes  so  that  one  could  not  see  the 
end."  5  (See  Fig.  128  and  plate  32.) 

Of  all  the  Antarctic  inland-ice  areas  studied,6  this  seems  to 
be  the  only  one  which  furnishes  a  parallel  to  the  continental 
glaciers  which  in  Pleistocene  times  existed  in  North  America 
and  in  Northern  Europe.  In  all  other  cases  a  rampart  of 
mountains  encloses  and  materially  modifies  the  physiography 
of  the  ice  surface.  It  is,  therefore,  much  to  be  regretted  that 
we  have  no  profile  across  its  surface. 

The  crests  upon  the  horizon  of  the  inland-ice  of  Kaiser 
Wilhelm  Land  appeared  not  straight,  but  gently  undulating. 
It  was,  therefore,  concluded  that  the  land  beneath  possesses 

a  similarly  undulat- 
ing character. 
Near  the  ice  margin, 
which  was  a  cliff 
130  to  165  feet 
high,  soundings 
made  through  the 
neighboring  sea-ice 
gave  depths  ranging 
from  550  to  810 
feet,  the  greater 
depths  lying  to  the  westward.  If  only  four-fifths  of  the 
ice  is  below  sea  level,  the  inland-ice  of  Kaiser  Wilhelm 
Land  must  be  aground  nearly,  if  not  quite  to  its  edge. 
This  is  proven  by  the  existence  of  a  tide  crack,  which  runs 
along  the  front  and  upon  which  the  sea-ice  moves  up  and 
down. 
The  convexly  curving  surfaces  of  the  marginal  zone  of  the 


FIG.  128.  —  The  inland-ice  of  Kaiser  Wilhelm  Land 
(after  von  Drygalski). 


PLATE  32. 


CONTINENTAL  GLACIER  WHERE  UNCONFINED     247 


inland-ice  are  thus  in  sufficiently  striking  contrast  with  the 
horizontal  top  so  characteristic  of  shelf-ice;  but  a  no  less 
noteworthy  difference  is  found  in  the  colors.  Even  from  a 
great  distance,  the  beautiful  blue  color  of  the  inland-ice  is 
noticeable,  whereas  the  shelf-ice  of  the  Ross  Barrier  is  daz- 
zling white.  The  blue  color  of  the  inland-ice  shows  that  its 
surface  is  in  general  free  from  snow,  and  this  appears  to  be 
characteristic  of  it  during  both  winter  and  summer.  Under 
the  strong  easterly  winds  which  prevail,  the  snow  falling 
upon  its  surface  is  able 
to  find  a  lodgment  only 
within  the  fissures  and 
in  the  lee  of  the  Gauss- 
berg. 

That  the  inland-ice  is 
moving  forward  is  suf- 
ficiently clear  from  the 
existence  of  great  gap- 
ing fissures  observed 
from  considerable  dis- 
tances. These  are  par- 

,          ,  .  .  100 200  joo 

ticularly  prominent    in  **«*.,-* 

the  Step-like  terraces  Of  FIG.  129.  —  Intersecting  series  of  fissures  in  the 
tV»P  npnr  mnro-in  nnr  surface  of  the  inland-ice  to  the  west  of  the 

the     near-margin    por      Gaussberg  (after  von  Drygalski). 
tions,  and  the  ice  shows 

bucklings  in  the  rear  of  them.  Crevasses  very  generally 
appear  upon  the  surface  in  parallel  series,  and  sometimes 
two  such  series  intersect  each  other  at  right  angles  (see 
Fig.  129). 

Such  fissures  were  sometimes  seen  as  they  opened  to  the 
accompaniment  of  rumbling  reverberations,7  and,  in  general, 
their  directions  seemed  to  correspond  to  local  disturbances 
above  buried  projections  of  the  floor,  or  else  to  the  strains  set 
up  due  to  general  movement.  The  effect  of  the  obstruction 


248         CHARACTERISTICS  OF  EXISTING  GLACIERS 

of  the  Gaussberg  in  the  path  of  the  moving  ice,  was  visible 
in  local  fissures  developed  within  its  neighborhood.8 

Measurements  of  the  rate  of  movement  within  the  ice 
were  made  during  a  period  of  five  months,  and  showed  that 
at  its  margin  the  inland-ice  moved  forward  at  the  remark- 
ably uniform  rate  of  about  a  foot  per  day.  At  a  distance 
of  two  kilometres  back  from  its  margin,  this  rate  had 
fallen  off  by  1|-  inches.9  In  spite  of  this,  the  aspect  of  the 
ice  front  was,  in  general,  one  of  rest.  No  evidence  of 
push  was  observed  along  its  base.10  In  the  vicinity  of  the 
only  exposed  land,  the  Gaussberg,  the  ice  surface  is  lowered 
within  a  broad  encircling  zone  due  to  the  greater  ablation  in 
consequence  of  heat  radiation  from  the  rock  surfaces  (see 
plate  33  A).  Here  the  stratification  within  the  ice  is  made 
apparent  by  lines  upon  the  surface,  though  elsewhere  the 
only  traces  of  banding  are  to  be  observed  in  fissures.  On  the 
surface  of  the  bands  were  found  the  indications  of  "  cryaco- 
nite  "  wells  and  water  basins,  no  doubt  from  dust  blown 
from  the  slopes  of  the  Gaussberg. 

It  has  been  stated  that  the  strong  easterly  winds  suffice 
to  keep  the  surface  of  the  inland-ice  swept  of  snow,  with  the 
exception  of  specially  protected  places  such  as  the  lee  of  the 
Gaussberg.  Thus  though  the  snow  fall  is  heavy,  the  evi- 
dence showed  that  instead  of  increasing  its  thickness,  the 
inland-ice  surface  is  being  constantly  lowered,  and  thus 
confirms  from  a  new  region  the  many  indications  that  the 
present  is  included  in  a  receding  hemicycle  of  glaciation. 
During  five  winter  months  the  ice  surface  was  found  to  have 
lowered  through  ablation  by  about  4  centimeters  (If  inches). 

The  Blue  Icebergs  of  Antarctica.  —  In  front  of  the  inland- 
ice  of  Kaiser  Wilhelm  Land  prodigious  fragments  of  the 
continental  glacier  were  found  ranged  in  series  more  or  less 
parallel  and  separated  only  by  narrow  lanes  (Gassen). 
Farther  out  from  the  margin  the  bergs  became  less  numerous 


CONTINENTAL  GLACIER  WHERE  UNCONFINED      249 

and  eventually  they  were  more  scattered  and  more  or  less 
promiscuously  frozen  into  the  surface  of  the  sea-ice. 

From  the  typical  tabular  bergs  of  the  Antarctic  seas,  these 
differ  strikingly  in  their  beautiful  blue  color  as  well  as  in 
their  rounded  contours.  In  Posadowsky  Bay  where  they 
are  frozen  into  the  sea-ice,  they  could  be  studied  to  advan- 
tage. Their  surfaces  were  found  to  be  intersected  by  broad 
furrows  which  were  steep  on  one  side  only,  and  smoothly 
polished  upon  the  other.11  The  rounding  of  the  angles  is  a 
result  of  filing  off  the  surface  by  hard  snow,  driven  by  the 
storm  winds.12 

These  blue  bergs  reveal,  especially  at  their  bases,  bands  of 
rock  debris  which  must  be  regarded  as  portions  of  the 
ground  moraine  which  have  been  raised  upon  a  subglacial 
obstruction,13  as  has  been  shown  to  be  characteristic  of  the 
margins  of  the  Greenland  continental  glacier.  The  rock 
debris  is  here  generally  found  in  layers  more  or  less  parallel 
to  the  blue  ice  strata.  The  individual  rock  fragments  are 
sometimes  angular  with  a  single  scratched  "  sole  "  cut  upon 
the  surface.  In  other  specimens  there  are  several  facets, 
or  the  block  may  be  entirely  covered  with  such  smoothed 
and  striated  surfaces. 

Professor  von  Drygalski,  in  his  classification  of  Antarctic 
icebergs,  has  expressed  his  belief  that  the  blue  bergs  arise 
from  the  common  tabular  bergs  through  the  action  of  the 
wind  driven  snow,  aided  by  evaporation.14  The  tabular 
bergs  he  believes,  further,  are  derived  from  the  margin  of 
the  inland-ice.  This  relationship  to  the  usual  tabular  bergs 
it  is  especially  difficult  to  accept,  since  the  blue  bergs  are 
found  mainly  in  contact  with  the  inland-ice  and  near  the 
shore,  and  are  further  characterized  by  the  same  colors  and 
structures,  whereas  the  usual  tabular  bergs  seem  to  have 
more  the  properties  of  shelf-ice,  though  a  portion  only  have 
the  absolute  uniformity  of  texture  found  in  the  best  known 
example  of  shelf-ice,  the  Ross  Barrier  (see  ante,  p.  239). 


250         CHARACTERISTICS  OF  EXISTING  GLACIERS 

Origin  of  the  West-ice.  —  The  peculiar  labyrinthine  surface 
of  the  West-ice,  and  its  resemblance  in  places  to  a  jam  of 
blue  bergs,  as  has  been  pointed  out  by  Drygalski,  in  the 
writer's  opinion,  permits  of  an  explanation  of  this  mass  of 
shelf-ice  which  is  quite  in  harmony  with  the  views  of  the 
British  and  Swedish  explorers  concerning  the  origin  of  shelf- 
ice  in  general.  As  von  Drygalski  has  stated,  the  inland-ice 
surface  of  Kaiser  Wilhelm  Land,  is  swept  clear  of  snow  by  the 
easterly  storm  winds,  the  sweepings  finding  lodgment  only 
in  fissures  and  protected  places.  A  crowded  fleet  of  blue  ice- 
bergs massed  upon  the  western  or  lee  shore  of  Posadowsky 
Bay  would  have  furnished  the  narrow  lanes  within  which 
the  snow  could  find  lodgment.  Still  further  to  the  west, 
the  intervening  spaces  would  have  been  levelled  up  with  the 
tops,  and  thus  a  relatively  even  surface  would  result. 

If  cumulative  loading  of  sea-ice  by  snow  is  to  be  assigned 
as  at  least  one  cause  of  the  formation  of  shelf-ice,  as  seems 
now  quite  generally  believed,  it  is  evident  that  this  process 
cannot  go  on  where  sea-ice  is  annually  broken  up  and  car- 
ried northward  with  the  ice  pack.  The  essential  condition 
for  its  formation  is,  therefore,  an  area  within  which  the  sea-ice 
either  attains  a  greater  thickness,  or  is  so  protected  by  the 
shores,  that  snow  accumulates  upon  it  from  year  to  year.  Now 
it  is  worthy  of  note  that  the  three  great  areas  where  shelf-ice 
has  thus  far  been  studied  have  all  this  character  in  common. 
The  Ross  Barrier  is  firmly  wedged  in  Ross  Sea  between 
Victoria  and  Edward  VII  Land.  The  "  terrace  "  of  West 
Antarctica  is  held  by  the  southeasterly  storms  against  the 
west  shore  of  a  great  gulf,  and  has  crowded  against  the 
hook-like  peninsula  of  West  Antarctica.  The  West-ice  of 
Kaiser  Wilhelm  Land  is  similarly  developed  upon  the  western 
or  lee  side  of  Posadowsky  Bay,  and  its  growth  has  been  appar- 
ently facilitated  by  the  assembling  of  a  fleet  of  icebergs  to 
collect  the  snow  swept  from  the  vast  surface  of  the  inland- 


CONTINENTAL  GLACIER  WHERE  UNCONFINED      251 

ice  to  the  south  and  east.  The  British  expeditions  to  Vic- 
toria Land  have  shown  that  vast  quantities  of  snow  blow  off 
the  barrier  into  the  sea,  and  the  collection  of  snow  upon  the 
northern  side  of  the  Nordenskiold  shelf-ice  tongue  is  most 
illuminating  in  this  connection  (see  ante,  p.  234). 

But  additional  evidence  of  this  essential  condition  for  the 
formation  of  shelf-ice,  has  been  furnished  by  the  recent 
French  explorations.  Gourdon  has  shown  that  near  West 
Antarctica  the  normal  winter's  thickness  of  field  ice  is  only 
about  16  inches,  whereas  in  the  sheltered  upper  end  of 
Flanders  Bay  it  had  reached  a  thickness  of  between  four 
and  five  metres  (13  to  16  feet).  Soft  snow  here  lay  upon  the 
surface,  with  stratified  neve  below  and  compact  ice  at  the 
bottom.  At  the  margin  of  this  terrace,  which  rose  to  a 
height  of  about  a  metre  above  the  sea,  immense  rafts  resem- 
bling in  form,  tabular  icebergs  were  from  time  to  time  (in 
February)  detached  on  long  rectilinear  cracks  intersecting 
the  terrace.15 

In  connection  with  the  latest  French  expedition  to  the 
Antarctic,  the  great  newly  discovered  bight  which  has  been 
named  Marguerite  Bay,  and  which  is  sheltered  behind 
Alexander  Island,  was  found  to  have  a  similarly  heavy  cover 
of  field  ice  reaching  a  thickness  in  this  instance,  of  from  2 
to  3  metres.  The  separation  of  ice  blocks  or  overgrown 
floes  from  the  margin,  took  place  with  fragmentation  and 
apparently  quite  resembled  the  calving  of  tabular  icebergs. 
Thus  from  the  meagre  reports  of  these  late  expeditions  which 
have  been  published,  it  would  appear  that  the  intermediate 
stages  in  the  transformation  of  field  ice  to  shelf  ice  by  accre- 
tion of  surface  snow  are  fast  being  supplied.16 

REFERENCES 

1  The  small  ice-cap  on  Louis  Philippi  Land  in  Northern  West  Ant- 
arctica was  in  1902  and  1903  crossed  by  Andersson  and  Duse  from  Hope 
Bay  to  Erebus  and  Terror  Gulf,  a  distance  of  about  22  miles  (Norden- 


252        CHARACTERISTICS  OF  EXISTING  GLACIERS 

skiold  and  Andersson,  "Antarctica,"  1905).  The  "upper  terrace"  which 
was  just  reached  by  Nordenskiold  near  King  Oscar  Land  probably  rep- 
resents inland  ice. 

2 Brown,  et  al.t  "The  voyage  of  the  'Scotia/   etc.,"  1906,  p.  236. 

3E.  Philippi,  I.e.,  p.  11. 

4  E.  von  Drygalski,  "  Zum  Kontinent  des  eisigen  Siidens,  Deutsche 
Siidpolarexpedition,  Fahrten  und  Forschungen  des  'Gauss,'  1901-1903," 
Berlin,  1904,  pp.  668,  21  pis.  and  maps  and  400  cuts.  E.  Philippi,  "  Ueber 
die  Landeis-Beobachtungen  der  letzen  fiinf.  Siidpolar-Expeditionen," 
Zeit.  f.  Gletscherk.,  vol.  2,  1907,  pp.  6-8. 

6  E.  von  Drygalski,  I.e.,  p.  241. 

6  The  "upper  terrace"  off  King  Oscar  Land  may  prove  to  be  another 
instance. 

7  Cf.  Peary,  ante  p.  129. 

8  E.  von  Drygalski,  "  Deutsche  Siidpolar-Expedition,  1901-1903,"  vol.  2, 
heft  I,  legends  of  plates. 

9  E.  von  Drygalski,  "  Die  Bewegung  des  Antarktischen  Inlandeises," 
Zeit.  f.  Gletscherk.,  vol.  1,  1906-1907,  pp.  61-65. 

10  E.  von  Drygalski,  "  Zum  Kontinent,  etc.,"  p.  305. 

11  This,  it  will  be  remembered,  was  a  characteristic  structure  upon  the 
surface  of  the  west-ice. 

12  E.  von  Drygalski,  "  Zum  Kontinent,  etc.,"  p.  305.     Also  Philippi,  I.e., 
p.  10. 

13  Philippi,  I.e.,  p.  11. 

14  E.  v.  Drygalski,  Sitzungsber.  bay.  Akad.  Wiss.,  Math.-Phys.  KL,  1910, 
pp.  10-13  (reprint). 

16  Gourdon,  Exp.  Ant.  Franc.,  1903-1905,  1908,  p.  125. 
16  Charcot,  "  Rapports  preliminaires,  etc.,"  1910,  p.  51. 


CHAPTER  XV 

THE    ANTARCTIC  CONTINENTAL  GLACIER  WHERE  BEHIND 
A  MOUNTAIN  RAMPART 

Inland-ice  in  Victoria  Land.  —  The  inland-ice  of  Victoria 
Land  unlike  that  in  Kaiser  Wilhelm  Land  is  held  within  an 
encircling  rampart  of  high  mountains  —  the  Admiralty, 
Prince  Albert,  Queen  Alexandra,  and  smaller  ranges  joined 
one  to  the  other  in  a  long  chain.  Its  physiography  is,  there- 
fore, in  important  respects  different  from  that  just  described. 
Held  back  by  the  ranges,  as  by  a  gigantic  retaining  wall,  the 
inland-ice  now  finds  an  outlet  through  somewhat  widely 
separated  and  relatively  narrow  portals.  These  gateways 
have  already  been  referred  to  as  outlets,  and  to  the  south- 
ward they  are,  so  far  as  known,  the  Skelton,  Mulock,  Barne, 
and  Shackleton  Inlets  and  the  Beardmore  Glacier  (see 
Fig.  134,  p.  258) ;  while  farther  to  the  north,  are  the  Reeves, 


GEOGRAPHICAL  -MILES 


FIG.  130.  —  Section  across  the  margin  of  the  inland-ice  of  Victoria  Land  in  a  direc- 
tion westward  from  McMurdo  Sound  (from  data  of  the  Scott  expedition) . 

David,  and  Ferrar  Glaciers.     Some  of  the  latter  are,  how- 
ever, apparently  no  longer  in  service  as  outlets  for  the  ice. 
Marginal  Cross  Sections  of  the  Inland-ice  along  the  Out- 
lets. —  Thanks  to  the  plucky  efforts  of  British  explorers,  we 

253 


254        CHARACTERISTICS  OF  EXISTING  GLACIERS 

are  fortunate  in  having  no  less  than  three  sections  across  the 
margins  of  the  inland-ice.  These  are  on  the  lines  of  the 
Beardmore  and  Ferrar  Glaciers,  and  between  the  David  and 
Reeves  Glaciers  —  the  Backstairs  Passage.  The  earliest  of 
these  was  made  by  Scott  on  an  east  and  west  line  westward 
from  McMurdo  Sound  and  up  the  Ferrar  outlet.  Later, 
Shackleton  made  his  section  more  nearly  upon  a  north  and 
south  line  up  the  Beardmore  outlet  and  toward  the  South 


Great  Ice  Barrier 


83°  82° 


tat.72-25'i  long.  155*  16' 


iwrticai  Scale  of  Feet 


Sta  Level 


FIG.  131  (a  and  6).  —  Section  across  the  Great  Ross  Barrier  and  up  the  Beardmore 
outlet  to  and  upon  the  ice  plateau  of  Central  Antarctica  (after  Shackleton,  but 
with  barrier  portion  added).  The  part  b  should  be  joined  to  the  right  of  a. 

(c)  Section  across  the  Drygalski  ice  barrier  tongue  and  up  the  Backstairs  Pas- 
sage on  to  the  inland-ice  in  a  direction  toward  the  south  magnetic  pole  (after 
David). 

Pole;  while  David  of  the  Shackleton  party  travelled  in  a 
direction  nearly  northwest  from  a  point  in  latitude  75°  S. 
up  toward  the  south  magnetic  pole  upon  the  plateau  (see 
Fig.  130  and  Fig.  131,  a,  b,  and  c).1 

While  not  large  when  compared  to  the  Ross  Barrier  to 
which  it  contributes  its  ice,  the  great  Beardmore  outlet  com- 
pared with  other  streams  of  ice  is  by  far  the  greatest  known. 
On  the  map  of  Fig.  134,  p.  258,  we  have  added  the  Great 


CONTINENTAL  GLACIER  BEHIND  A  RAMPART      255 


Aletsch  Glacier  of  Switzerland  drawn  to  the  same  scale  in 

order  to  bring  out  this  

contrast.  The  area  of 
the  Beardmore  outlet 
is  in  excess  of  5000 
square  miles,  its  width 
is  in  places  about  50 
miles,  and  its  fall 
about  6000  feet  with 
an  average  of  60  feet 
to  the  mile  through- 
out its  entire  length. 
Its  surface  showed 
every  variety  from 
soft  snow  to  cracked 
blue  ice.  Crevasses 
were  everywhere,  some 
of  them  descending  to 
hundreds  and  perhaps 
even  a  thousand  feet. 
An  ancient  medial 
moraine  was  largely 
buried  beneath  its 
surface. 

All  the  sections  up 
the  outlets  show  in 
common  a  steep  slope 


h 


near    the    margin    and     FlG>   132.  _  Comparison  of  sections  across  the 

gentler  grades  above; 
as  was  found  to  be 
characteristic  also  of 
the  margins  of  the 
Greenland  continental 
glacier  —  an  ice  body 


margins  of  the  continental  glaciers  of  Green- 
land and  Antarctica.  (a)  West  Greenland 
(Peary) ;  (6)  West  Greenland  (Nordenskiold) ; 
(c)  Southwest  Greenland  (Nansen) ;  (d)  South- 
east Greenland  (Nansen) ;  (e)  South  Greenland 
(Garde)  ;  (/)  Victoria  Land  west  of  McMurdo 
Sound  (Scott) ;  (g)  South  Victoria  Land 
(Shackelton) ;  (h)  North  Victoria  Land,  Ant- 
arctica (David). 


256        CHARACTERISTICS  OF  EXISTING  GLACIERS 

similarly  held  in  by  a  wall  of  mountains  (see  Fig.  132). 
The  Antarctic  sections  are  like  them  also  in  the  step-like 
alternation  of  steeper  and  more  gradual  slopes  in  the  vicin- 
ity of  the  margins,  the  steeper  slopes  being  deeply  crevassed 
in  a  transverse  direction. 

Once  the  plateau  surface  has  finally  been  reached,  all 
sections  are  alike  in  the  monotony  of  the  surface,  no  irregu- 
larities in  excess  of  a  hundred  feet  being  encountered.  All 
irregularities  of  surface  are  here  due  to  sastrugi  deposited  and 
later  cut  out  by  the  fierce  blizzards  from  the  surface  of  the 
plateau.  The  plateau  is,  however,  in  no  case  reached  when 
the  mountain  rampart  has  been  passed,  though  the  surface 
slopes  continue  to  become  more  gradual.  Within  its  retain- 
ing mountain  wall  the  surface  of  the  inland-ice  is,  therefore, 
flatly  domed  or  shieldlike.  It  is  the  same  in  general  form, 
though  on  a  vastly  grander  scale,  as  the  domed  ice  islands 
encountered  off  the  coast  (Fig.  110  and  pi.  29  A).  Above  the 
great  Beardmore  outlet  the  surface  continues  to  rise  in  ter- 
races with  crevasses  upon  the  steeper  slope,  and  these  very 
properly  led  Shackleton  to  the  belief  that  the  ice  here  rests 
in  moderate  thickness  upon  a  steeply  sloping  floor.  The 


FIG.  133.  —  View  from  above  the  Ferrar  outlet  looking  from  the  inland-ice  toward 
the  outlet  and  showing  the  dip  of  the  surface  produced,  by  the  indraught  of  the 
ice  (after  Scott). 

ridges  rise  abruptly  with  a  great  crevasse  at  the  top  of  each 
and  a  descent  upon  the  other  side  of  perhaps  fifty  feet  on  a 
grade  of  one  in  three.  Then  smaller  ridges  and  new  waves 
of  pressure  ice  are  encountered,  the  undulations  of  the  first 


CONTINENTAL  GLACIER  BEHIND  A  RAMPART      257 

order  of  magnitude  being  separated  by  an  interval  of  about 
seven  miles. 

Dimples  upon  the  Ice  Surface  above  the  Outlets.  —  In 

Greenland  it  was  found  that  the  tongues  of  ice  which  push 
out  through  gaps  in  the  mountain  wall,  the  outlets,  show 
above  them  a  dimple  in  the  surface  caused  by  the  indraught 
of  the  ice  from  the  near-lying  portions  of  the  plateau.2  The 
same  characters  pertain  to  the  ice  of  Victoria  Land.3  A 
photograph  by  Scott  looking  back  on  the  line  of  his  route 
toward  the  outlet  up  which  he  had  come,  shows  this  very 
clearly.  In  Fig.  133,  drawn  from  his  view,  we  have  added 
a  dashed  line  to  bring  out  the  dip  in  the  ice  surface.  Farther 
down  the  outlet  this  concavity  of  the  ice  surface  obtains,4 
but  in  the  lower  reaches  it  changes  to  a  convexly  moulded 
form.  Upon  the  Beardmore  outlet  this  concavity  of  the 
surface  with  tendency  to  form  an  amphitheatre  above  is 
brought  out  upon  Shackleton's  map  (see  fig.  134). 

Above  the  Ferrar  Outlet  Scott  found  the  transition  from 
the  neve  surface  of  the  plateau  to  the  outlet  ice  not  a  gradual 
one,  but  abrupt,  the  outlet  having  a  corrugated  surface  of 
massive  blue  ice.  The  surface  of  the  plateau  ice  is  every- 
where carved  by  the  wind  drift  to  form  sastrugi  of  erosion 
which  will  be  discussed  in  connection  with  the  winds  of  the 
plateau. 

Ice  Aprons  below  Outlets.  —  At  the  foot  of  each  active 
outlet,  the  ice  is  discharged  upon  the  shelf-ice  in  an  ice  apron 
which  spreads  out  laterally  as  well  as  in  front  (see  fig.  134). 
In  front  of  the  Beardmore  outlet  this  apron  rises  to  a  height 
near  its  medial  line  of  between  400  and  500  feet  above  the 
general  level  of  the  barrier  surface. 

Moats  about  Rock  Masses.  —  About  the  continental  glacier 
of  Greenland  wherever  the  rock  projects  through  its  surface, 
local  melting  results  from  heat  radiation  from  the  rock  sur- 
face (see  p.  169).  Except  when  filled  in  with  drifted  snow 


258        CHARACTERISTICS  OF  EXISTING  GLACIERS 


FIG.  134.  —  Map  of  the  Beardmore  Outlet  from  the  inland-ice  of  Antarctica  to  the 
Ross  Barrier.  Note  the  dimple  at  head  and  ice  apron  at  foot  (after  Shackleton). 
In  the  same  scale  the  Great  Aletsch  glacier  (A)  is  added. 


PLATE  33. 


A.   The  Gaussberg  of  Kaiser  Wilhelm  Land  with  ice  surface  depressed  about  it  (after  v. 

Drygalski). 


B.    Moat  surrounding  projecting  rock  mass.     Inland-ice  of  Victoria  Land   (after  Scott), 


CONTINENTAL  GLACIER  BEHIND  A  RAMPART     259 

or  when  ice  pressure  has  closed  this  gap,  a  deep  and  narrow 
depression  surrounds  the  rock  mass.  This  has  been 
designated  a  moat  from  its  resemblance  to  the  moat  sur- 
rounding a  castle.5  The  same  holds  true  of  Victoria  Land, 
where  the  wall  of  mountain  ranges  offers  essentially  the 
same  conditions  (see  Plate  33  B). 

Mountain  Glaciers  on  Outer  Slope  of  the  Retaining  Ranges. 
-  Many  of  the  well-known  types  of  mountain  glaciers  6  are 
found  in  numbers  on  the  outer  slope  of  the  mountain  wall 
which  hems  in  the  continental  glacier  of  Victoria  Land. 
The  scale  of  these  is  large,  like  everything  in  the  region,  but 
the  internal  movement  in  most  cases  is  slight,  and  the  larger 
number  are  in  a  relatively  stagnant  condition.  The  Blue 
Glacier,  which  starts  in  the  Royal  Society  Range,  is  cited  by 
Ferrar  as  an  example  of  the  Norwegian  ice  cap  type,7  and  ends 
at  tide  water  in  a  cliff  between  70  and  80  feet  high  on  Mc- 
Murdo  Sound.  Glaciers  of  the  Alpine  type  occur  according 
to  the  same  authority  in  great  profusion  in  the  Royal  Society 
Range.  With  them  are  associated  horse-shoe  or  corrie 
glaciers,  and  these  are  especially  well  represented  at  the  foot 
of  the  Inland  Forts.  The  presence  of  the  cirques  here  as 
everywhere  calls  attention  to  the  peculiar  eroding  process 
which  distinguishes  mountain  glaciers  from  their  mightier 
neighbors  of  the  continental  type. 

There  is  but  little  superglacial  material  upon  the  surface  of 
the  mountain  glaciers,  the  lateral  and  medial  moraines  of  the 
Ferrar  glacier  being  merely  long  lines  of  large  stones  with 
very  little  finer  material.  About  the  margins,  however,  mo- 
raines are  found  near  the  bottom  intercalated  with  blue  ice, 
and  at  one  point  englacial  rock  debris  was  seen  pushed  up  to 
form  a  surface  moraine  where  two  glaciers  meet  coming  from 
opposite  directions. 

Ice  Slabs.  —  Glaciers  of  an  essentially  new  type,  which 
Ferrar  has  referred  to  as  ice  slabs,  are  in  the  cases  which  he 


260        CHARACTERISTICS  OF  EXISTING  GLACIERS 

cites  masses  of  ice  about  50  feet  in  thickness  and  from  4  to  6 
square  miles  in  area.  These  appear  to  be  the  dead  aprons  of 
true  piedmont  glaciers,  from  which  the  feeders  have  disap- 
peared. They  offer  the  most  striking  illustration  of  the  ne- 
cessity for  some  modification  of  our  views  concerning  the 
nourishment  and  ablation  of  glaciers  in  polar  latitudes,  where, 
as  we  shall  see,  wind  may  be  a  far  more  important  factor 
than  temperature,  and  where  melting  occurs  only  under 
special  conditions.  These  ice  slabs  seem  clearly  to  be  the 
relics  of  piedmonts  retained  during  a  receding  hemicycle  of 
glaciation.  Were  the  changes  in  their  form  and  size  due  ta 
a  general  rise  of  the  air  temperature  only,  since  the  slabs  are 
in  the  lower  levels,  they  should  first  disappear;  but  where 
there  is  practically  no  melting  at  all  save  in  the  vicinity  of 
exposed  rock  surfaces,  or  in  connection  with  strong  local 
foehn  winds,  the  relatively  narrow  and  tributary  ice  streams,, 
surrounded  as  they  are  on  all  sides  by  rock,  would  probably 
be  the  first  to  disappear.  The  mountain  valleys,  moreover, 
are  the  natural  channels  of  the  hot  and  dry  foehn  winds.8  If 
formed  below  true  outlets  from  the  inland  ice,  the  recession 
of  the  parent  ice  mass  would  alone  suffice  to  explain  them,, 
since  this  might  cut  off  their  nourishment. 

REFERENCES 

1  R.  F.  Scott,  "  The  Voyage  of  the  '  Discovery,' "  2  vols.,  1905.     E.  H. 
Shackleton,  "  The  Heart  of  the  Antarctic,"  2  vols.,  1910. 

2  Hobbs,  Proc.  Am.  Phil.  Soc.,  vol.  49,  1910,  pp.  87-90. 

3  Scott,  I.e.,  voL  2,  pi.  opp.  p.  240,  lower  view. 

4  Scott,  I.e.,  pi.  opp.  p.  224,  upper  view. 

5  Proc.  Am.  Phil.  Soc.,  vol.  49,  p.  117. 

6  Geogr.  Jour.,  vol.  35,  1910,  pp.  147-148. 

7  Ferrar,  I.e.,  pp.  462-463. 

8  David,  I.e.,  p.  151. 


CHAPTER  XVI 

CLIMATIC    CONDITIONS   WHICH    AFFECT    THE   NOURISH- 
MENT OF  ANTARCTIC  ICE  MASSES 

The  Greenland  Ice  in  its  Relation  to  the  Antarctic  Conti- 
nental Glacier. — The  conditions  of  climate  which  determine 
the  alimentation  of  ice  masses  within  polar  regions  are  not 
identical  with  those  which  have  been  worked  out  from  study 
of  the  local  mountain  glaciers  which  now  exist  in  low  lati- 
tudes. This  has  already  been  pointed  out  for  the  great  con- 
tinental glacier  of  Greenland.1  It  was  found  that  the  vast 
surface  of  the  ice  dome  of  Greenland  controls  the  air  circula- 
tion above  it ;  and  we  see  that  in  proportion  to  their  dimen- 
sions great  continental  glaciers  must  exert  larger  and  larger 
effects,  and  even,  it  may  be,  eventually  put  a  limit  upon  their 
own  extension. 

The  continent  of  Greenland  is  not  located  in  proximity  to 
the  pole,  and  hence  we  are  able  the  better  to  assert  that  the 
conditions  which  we  there  find  are  not  explained  by  the  plan- 
etary system  of  the  winds.  This  is  fortunate  for  our  study  of 
the  Antarctic  region,  since  there  an  elevated  plateau  is  more 
nearly  centred  above  the  earth's  axis,  and  more  or  less  un- 
known and  mysterious  causes  might  otherwise  be  invoked 
to  explain  a  system  of  circulation  and  a  climatic  condition 
which  in  most  respects  are  identical  with  those  worked  out 
with  some  care  for  the  northern  continental  glacier.  For 

261 


262         CHARACTERISTICS   OF  EXISTING  GLACIERS 

these  reasons  the  northern  ice  masses  should  be  studied  first, 
because  of  the  light  which  they  throw  upon  the  problems  of 
Antarctic  glaciation. 

Air  Temperatures,  Humidity,  and  Insolation.  —  The  Antarc- 
tic, as  already  pointed  out  in  an  earlier  section,  is  in  contrast 
to  Arctic  regions,  characterized  by  greater  severity  of  climate, 
by  lower  average  annual  temperatures,  and  by  less  tempera- 
ture range  between  winter  and  summer  (ante,  p.  188).  Over 
the  Greenland  ice  the  relative  humidity  of  the  air  is  extremely 
high,  while  its  absolute  humidity,  because  of  low  temperature, 
is  very  low.  Even  on  the  margins  of  the  Antarctic  continent 
this  was  early  proved  to  hold  true.  On  between  thirty  and 
forty  per  cent  of  the  days  that  he  was  south  of  the  parallel  of 
60°  S.,  Ross  found  the  air  completely  saturated  with  moisture. 
Racovitza  reports  from  the  "  Belgica  "  expedition  that  the 
air  was  almost  constantly  saturated  with  water  vapor.2 

Insolation,  or  solar  radiation,  on  the  borders  of  Antarctica 
is  during  the  summer  months  considerable.  On  the 
"  Belgica  "  expedition  at  the  end  of  December,  Racovitza 
found  that  a  black-bulb  thermometer  when  exposed  in  the 
sun  registered  113.2°  F.,  when  the  air  temperature  was  only 
31.6°  F.,  although  this  effect  was  hardly  felt  upon  the  ice 
pack.3  Bernacchi  with  a  black-bulb  thermometer  frequently 
obtained  at  Cape  Adare  temperatures  above  80°  F.,  while 
temperatures  in  the  shade  were  below  the  freezing  point.4 

Nature  of  the  Snow  Precipitated  in  Antarctica.  —  Rain  is 
unknown  on  the  Antarctic  continent  and  most  of  the  snow  is 
precipitated  in  spring  and  summer5  and  at  relatively  low  tem- 
peratures. Observations  made  in  Victoria  Land  have  shown 
that  if  precipitated  near  the  freezing  point,  the  snow  is  of  one 
or  the  other  of  two  types.  With  a  sudden  fall  of  temperature 
the  sago  or  tapioca  snow  was  precipitated  in  the  form  of  felted 
spheres  one-tenth  of  an  inch  or  more  in  diameter.  Other- 
wise large  six-rayed  feathery  flakes  similar  to  those  formed  in 


NOURISHMENT  OF  ANTARCTIC  ICE  MASSES        263 

warmer  climates  resulted.  In  colder  temperatures  the  air 
became  filled  with  minute  ice  crystals  which  were  only  one 
one-hundredth  of  an  inch  in  diameter  and  descended  from  a 
cloudless  sky.6  This  form  of  snow  thus  resembles  the  "  frost 
snow  "  described  by  Nansen  as  characteristic  of  the  ice 
plateau  of  Greenland. 

When  the  softer  snow  falls  in  summer  time,  if  the  weather 
becomes  colder,  the  snow  compacts  itself  and  becomes  hard. 
Such  superficial  hardening  yields  a  "  pie-crust  "  surface  and 
the  snow  below  is  soon  firmly  bound  together  so  as  to  yield 
the  usual  "  smooth-sledging  type  of  winter  snow-ice." 

Upon  the  plateau  a  surface  of  somewhat  different  character 
is  produced  when  solar  radiation  on  quiet  summer  days  has 
melted  a  thin  superficial  layer  of  the  snow.  Under  such  con- 
ditions large  and  beautiful  reconstructed  ice  crystals  develop 
which  are  about  one-half  inch  across  and  one-sixteenth  of  an 
inch  in  thickness.  These  develop  throughout  a  layer  extend- 
ing about  one-half  an  inch  below  the  surface.  Covered  with 
these  sheets  of  brightly  reflecting  ice  crystals,  the  snow  sur- 
face glitters  "  like  a  sea  of  diamonds." 7  The  heavy  sledge 
runners  rustle  as  they  crush  the  crystals  by  the  thousand. 
With  the  first  strong  wind  these  crystals  are  picked  up  and 
drifted  away,  the  sastrugi  in  consequence  exhibiting  such 
scaly  crystals  on  their  lee  sides,  whereas  the  windward 
surfaces  are  much  eroded  and  furrowed  by  the  wind.8 

Off  Kaiser  Wilhelm  Land  it  was  noticed  that  late  in  August 
when  the  actinometer  had  risen  for  the  first  time  above  freez- 
ing, traces  of  fusion  began  to  appear  upon  the  snow  surface. 
These  consisted  in  a  smoothening  and  hardening  of  the  sur- 
face, and  in  the  development  of  sublimed  crystals  beneath 
the  crust.  This  last  feature  was,  moreover,  not  found  in 
those  crusts  which  were  formed  by  wind  pressure  and  were 
observed  alike  upon  the  north  and  south  sides  of  drifts.9  The 
amount  of  the  annual  snow  fall  above  the  Great  Barrier  has 


264         CHARACTERISTICS  OF  EXISTING  GLACIERS 

already  been  discussed  (see  ante,  p.  223).  Upon  the  plateau 
snow  is  carried  in  the  air  and  was  observed  to  within  110 
miles  of  the  pole.  It  is  significant  that  the  snow  comes 
mainly  in  the  summer  time  and  invariably  from  the  south 
or  southwest  in  connection  with  the  peculiar  blizzards.  On 
several  occasions  it  was  observed  that  whereas  in  the  earlier 
part  of  the  blizzard  the  snow  was  largely  redistributed  snow 
in  the  form  of  drift,  a  new  fallen  snow  appeared  near  the  end 
accompanied  by  a  rise  of  temperature  (see  below,  p.  269). 10 

Winds  upon  the  Continental  Margins.  —  Throughout  the 
margins  of  the  Antarctic  regions  the  general  direction  of 
strong  surface  winds  seems  to  be  within  the  quadrant  be- 
tween south  and  east.  In  this  Wilkes,  Ross,  Wyville  Thom- 
son, and  other  navigators  of  the  far  southern  seas  are  in 
agreement.  The  zone  of  prevailing  westerlies  travelling 
southward  with  'the  sun  may,  however,  at  points  near  the  Ant- 
arctic Circle  sometimes  bring  about  a  partial  seasonal  reversal 
of  this  wind  direction.  Thus  Arctowski  reported  high  air 
pressure  at  the  solstices  and  low  pressure  at  the  equinoxes  to 
the  westward  of  West  Antarctica,  with  easterly  winds  pre- 
dominating over  westerly,  but  with  a  relative  high  frequency 
of  the  latter  in  the  winter  months.11 

At  Cape  Adare  in  Victoria  Land  the  prevailing  winds  were 
found  by^Bernacchi  to  be  from  the  east-southeast  and  south- 
east in  a  very  marked  degree.  Measured  in  observation 
hours  the  calms  were,  however,  even  more  important,  there 
being  1033  hours  of  calms,  973  hours  of  winds  from  the  south- 
easterly quadrant,  and  only  275  hours  of  winds  from  all 
westerly  points  whatsoever.12 

At  Cape  Royds  on  McMurdo  Sound,  where  Scott 's  expedi- 
tion wintered,  the  winds  were  much  modified  by  local  condi- 
tions, but  were  generally  from  the  east  or  southeast.  No 
winds,  but  only  light  airs,  came  from  the  west  or  northwest. 
Blizzards  invariably  came  from  the  south  or  southwest.13 


NOURISHMENT  OF  ANTARCTIC  ICE  MASSES        265 

The  Shackleton  party  in  almost  the  same  locality  reports 
either  gentle  northerly  winds  whose  velocity  seldom  exceeded 
twelve  miles  an  hour,  or  winds  from  the  south-southeast  or 
southwest,  the  latter  ranging  from  gentle  breezes  to  fierce 
blizzards.  A  northwesterly  wind  was  rare.14 

In  Kaiser  Wilhelm  Land  an  absolute  rule  of  easterly  winds 
was  observed,  and  gales  from  the  southeast  kept  the  surface 
of  the  inland-ice  swept  clear  of  snow.15 

The  Antarctic  Continental  (Glacial)  Anticyclone.  —  The 
prevalence  of  southeasterly  winds  about  the  borders  of  the 
Antarctic  continent  finds  its  only  explanation  in  the  exist- 
ence of  an  area  of  high  atmospheric  pressure  above  the 
continent.  Sir  James  Ross,  as  long  ago  as  1840,  obtained 
increasingly  high  atmospheric  pressures  in  his  cruise  south- 
ward in  the  Ross  Sea.  A  South  Polar  anticyclone  was  as 
early  as  1893  declared  to  exist  by  Sir  John  Murray  in  a  paper 
read  before  the  Royal  Geographical  Society  and  printed  in  the 
Geographical  Journal.16  Unfortunately  the  theory  of  polar 
eddies  promulgated  by  Ferrel17  and  adopted  by  Davis  in  his 
in  many  respects  excellent  treatise 18  is  responsible  for  a 
general  prevalence  of  incorrect  views  concerning  the  winds 
of  both  the  earth's  polar  regions.  As  pointed  out  by 
Buchan  in  1898,  the  low  pressures  required  by  this  theory 
do  not  exist,  and  in  place  of  the  supposed  northwesterly 
winds  blowing  homeward  toward  the  poles,  as  required  by 
the  theory,  we  find  in  the  Antarctic  southeasterly  and  east- 
erly ones.19  If  Ferrel's  theory  were  correct,  Antarctica 
would  be  a  land  of  rain  and  fog  instead  of  what  it  is  known 
to  be. 

Bernacchi  in  1901,  as  a  result  of  his  very  important  mete- 
orological studies  in  connection  with  the  "  Belgica  "  expedi- 
tion, set  forth  the  evidence  for  the  Antarctic  anticyclone  in 
a  most  convincing  manner.  Speaking  of  the  prevailing 
southeasterly  winds  of  the  region,  he  says:  — 


266        CHARACTERISTICS  OF  EXISTING  GLACIERS 

Their  frequency  and  force,  the  persistency  with  which  they 
blow  from  the  same  direction,  the  invariable  high  rise  in  the  tem- 
perature, their  dryness,  the  motion  of  the  upper  clouds  from  the 
N.W.,  and,  finally,  the  gradual  rise  in  the  mean  height  of  the 
barometer  to  the  south  of  about  latitude  73°  S.,  seem  to  indicate 
that  the  Antarctic  lands  are  covered  by  what  may  be  regarded 
practically  as  a  great  permanent  anticyclone,  with  a  higher  press- 
ure than  prevails  over  the  open  ocean  to  the  northward.20 

The  complete  verification  of  the  existence  of  an  Antarctic 
anticyclone  has,  however,  been  furnished  by  Shackleton, 
who  in  his  journey  across  the  ice  plateau  to  within  one  hun- 
dred and  ten  miles  of  the  earth's  southern  pole  has  brought 
back  the  knowledge  that  throughout  the  entire  distance  the 
winds  blew  strongly  nearly  all  the  time  from  the  south  or 
southeast  with  an  occasional  change  to  the  southwest,  and 
that  all  sastrugi  pointed  to  the  southward.21 

Wind  Direction  determined  by  Snow-ice  Slope.  —  It  is 
the  author's  belief  that  over  the  Antarctic  continent  this 
anticyclonic  circulation  of  the  air  is  not  determined  in  any 
sense  by  latitudes,  but  is  a  consequence  of  air  refrigeration 
through  contact  with  the  elevated  snow-ice  dome,  thus 
causing  air  to  slide  off  in  all  directions  along  the  steepest 
gradients.  For  the  continent  of  Greenland  this  has  now  been 
fully  demonstrated  through  the  work  of  several  observers, 
but  especially  of  Commander  Peary; 22  and  there  is  every 
reason  to  think  that  the  conditions  in  Antarctica  are  essen- 
tially the  same.  Upon  this  supposition  the  prevalent  winds 
and  the  strongly  marked  sastrugi  which  were  observed  by 
Scott,  Shackleton,  and  David  upon  the  ice  plateau,  find  a 
simple  explanation.  The  strikingly  local  character  of  the 
winds  about  the  margins  of  the  great  Ross  Barrier  are  on 
this  assumption  likewise  accounted  for. 

As  already  stated,  Shackleton  encountered  on  his  journey 
of  about  two  hundred  miles  across  the  ice  plateau  strong 


NOURISHMENT  OF  ANTARCTIC  ICE  MASSES        267 


winds  blowing  only  from  the  southerly  quarter,  and  the 
sastrugi  showed  this  direction  only.  Scott  on  his  plateau 
journey  westward  for  about  two  hundred  miles  from 
McMurdo  Sound,  in  a  latitude  eight  to  ten  degrees  lower, 
likewise  encountered  winds  of  constant  direction  here  from 
the  west-southwest,  and  a  single  set  of  sastrugi  with  direc- 
tions varying  only  between  west  by  south  and  southwest 
by  west.  Eight  to  ten  degrees  farther  north,  and  upon  what 
now  appears  to  be  a  relatively  narrow  peninsula  of  the  con- 


539 


•^  c 


FIG.  135.  — 'Sketch  map  showing  directions  of  the  sastrugi  along  the  line  of  David's 
course  to  the  south  magnetic  pole.  The  direction  of  the  arrows  indicates  the 
direction  of  the  wind  as  evidenced  by  the  sastrugi  (based  on  Shackleton's  map 
and  David's  narrative). 

tinent,  David  for  the  first  time  found  variable  wind  direc- 
tions and  several  sets  of  sastrugi.    A  more  careful  examina- 


268         CHARACTERISTICS  OF  EXISTING  GLACIERS 

tion  of  his  data  confirms  the  view  that  the  air  currents  upon 
the  peninsula  are  determined  wholly  by  the  direction  of 
snow  slope  upon  the  plateau,  as  is  apparent  from  Fig.  135. 
Off  the  coast  the  sastrugi  betrayed  the  evidence  of  the  strong 
southerly  blizzards  and  also  of  winds  which  blew  down  from 
the  plateau  through  the  portals  of  the  outlets.  Until  the 
highest  point  of  the  plateau  had  been  reached,  winds  and 
sastrugi  alike  indicated  a  sliding  down  on  the  slopes  toward 
the  coast.  On  January  llth,  when  there  was  "  no  appreciable 
general  up-grade  now/'  it  was  noticed  that  the  sastrugi 
"  had  now  changed  direction,  and  instead  of  trending  from 
nearly  west  or  north  of  west,  eastwards,  now  came  more  from 
the  southeast  directed  towards  the  northwest.'7  To  the 
west  of  the  summit  as  shown  by  the  map,  the  sastrugi  point 
southeastward,  indicating  that  the  shore  line  doubtless 
continues  its  direction  to  the  westward  from  Cape  North. 
Returning  from  the  South  magnetic  pole  toward  the  crest 
of  the  dome,  David  states,  "  We  had  seen  from  the  evidence 
of  the  large  sastrugi  that  blizzards  of  great  violence  must 
occasionally  blow  in  these  quarters,  and  from  the  direction  of 
the  sastrugi  during  our  last  few  days'  march,  it  was  clear  that 
the  dominant  direction  of  the  blizzard  would  be  exactly  in 
our  teeth."  23 

The  Foehn  Blizzard  of  the  Ice  Plateau.  —  Next  to  the  obser- 
vation that  the  prevailing  winds  blow  outward  from  the 
interior  of  the  continent,  the  nature  of  the  winds  themselves 
is  most  characteristic  of  an  anticyclone  developed  above  an 
ice  plateau  as  we  have  become  familiar  with  it  in  Greenland. 
In  Victoria  Land  these  winds  sometimes  blow  with  a  violence 
of  seventy  to  eighty-five  or  more  miles  per  hour,  and  are  prob- 
ably the  most  violent  that  are  anywhere  known.  The 
summer  blizzard  lasting  for  three  days,  which  Shackleton 
encountered  near  his  farthest  south  and  at  an  elevation  in 
excess  of  10,000  feet  may  be  cited  as  an  example.24 


NOURISHMENT  OF  ANTARCTIC  ICE   MASSES        269 

Despite  the  fact  that  these  blizzards  in  summer  at  least 
appear  to  bring  snow,  the  wind  may  be  described  as  dry. 
Though  at  first  cold,  and,  in  fact,  having  its  origin,  it  would 
appear,  in  a  general  lowering  of  the  temperature  during  a 
period  of  calm,  in  a  later  stage  the  temperature  rapidly  rises, 
due  to  the  foehn  effect.  In  Victoria  Land  an  increase  of 
as  much  as  45°  F.  has  been  observed  to  take  place  within 
twenty-four  hours. 

The  sequence  of  events  during  a  blizzard  begins  with  gentle 
northerly  winds  which  continue  for  a  day  or  two,  during 
which  temperatures  are  low.  David  has  suggested  that  dur- 
ing this  time  air  is  flowing  south  to  take  the  place  of  air 
whose  volume  has  been  reduced  as  a  result  of  the  heat  ab- 
stracted from  it  on  the  ice  surface.  Then  there  follow  two 
or  three  days  of  absolute  calm,  during  which  the  temperature 
continues  to  fall.  Still  further  cooled  upon  the  ice  surface, 
the  air,  a  week  or  more  after  the  calm  begins,  starts  to  move 
outward  in  all  directions  and  so  develops  (on  the  edge  of  the 
barrier)  a  southeasterly  blizzard.  Simultaneously  with  this 
movement  the  steam  cap  over  the  volcano  of  Erebus,  which 
normally  indicates  an  upper  current  from  the  northwest, 
swings  round  to  the  north  and  takes  on  an  accelerated  move- 
ment, as  though  it  were  being  drawn  from  that  direction  to 
supply  air  to  the  void  resulting  from  the  violent  surface  cur- 
rent toward  that  direction.  Corresponding  to  the  increased 
velocity,  the  normal  foehn  effect  near  the  pole  must  be  much 
increased,  as  it  is  also  on  the  descent  of  the  surface  current 
from  the  plateau.  As  soon  as  the  warming  of  the  polar 
air  from  this  cause  has  become  general,  the  high  air  pressure 
of  the  central  area  is  automatically  reduced,  and  thus  the 
blizzard  gradually  brings  about  its  own  extinction.  To  the 
warming  effect  of  the  descending  air  current  there  is  rather 
suddenly  added  the  latent  heat  of  condensation  of  the 
moisture  when  it  is  precipitated  in  the  form  of  fine  ice 


270         CHARACTERISTICS  OF  EXISTING  GLACIERS 

crystals  within  the  air  layers  just  above  the  snow-ice  sur- 
face. The  rather  sudden  termination  of  the  blizzard  may 
be  thus  in  part  explained.  David  has  suggested  that  a 
"  hydraulic  ram  effect  "  may  be  induced  in  the  air  of  the 
upper  currents,  since  the  steam  clouds  over  Erebus,  nor- 
mally the  antitrades,  are  temporarily  reversed  in  direction 
at  the  termination  of  a  blizzard,  and  for  a  short  interval 
blow  northward.26 

Foehn  winds  were  experienced  by  the  German  expedition 
off  Kaiser  Wilhelm  Land,  and  von  Drygalski  has  remarked 
upon  the  fact  that  the  air  above  the  inland-ice  is  more  trans- 
parent than  that  over  the  neighboring  sea-ice,  this  arising 
from  its  greater  dryness  due  to  its  dropping  down  from  the 
heights  in  the  interior.  Frozen  sleeping  bags  exposed  in  the 
day-time  on  the  slopes  of  the  Gaussberg  became  soft  and 
dry  within  a  surprisingly  brief  time,  and  particularly  during 
the  storms.  An  ice  wall  built  up  about  the  tent  was  so 
sucked  up  by  the  dry  wind  as  to  present  an  indented  and 
ragged  surface.26 

The  local  effect  of  the  foehn  is  naturally  accentuated  within 
the  steep  and  relatively  narrow  outlets  from  the  interior 
plateau.  When  ascending  to  the  plateau  from  the  Drygalski 
tongue,  David  encountered  a  hot  foehn  which  thawed  the 
snow,  and  upon  the  glacier  tongue  below  the  effects  of  earlier 
foehns  were  found  in  the  channelled  surface  and  the  buried 
water  tunnels.27 

At  the  winter  station  of  the  Swedish  Antarctic  Expedition 
on  Snow  Hill  Island,  West  Antarctica,  even  in  the  most 
severe  winter  weather,  sudden  rises  of  temperature  occurred 
which  lasted  for  a  few  minutes  only,  but  which  carried  the 
mercury  in  the  thermometer  up  to  9j°  C.  (49°  F.),  a  point 
higher  than  is  reached  even  in  the  summer  season.  Such 
remarkably  abrupt  changes  Nordenskiold  believes  can  only 
be  explained  by  very  sudden  falls  of  air,  which  in  consequence 
become  heated  adiabatically.28 


NOURISHMENT  OF  ANTARCTIC   ICE  MASSES        271 

The  discovery  of  the  origin  of  both  the  Greenlandic  and 
Antarctic  warm  winds  in  a  refrigeration  of  surface  air  layers 
by  contact  with  snow-ice  masses  raises  the  question  whether 
the  so-called  foehn  winds  of  mountain  regions  have  not  a 
similar  cause  in  contact  refrigeration.  It  is  thus  of  special 
interest  to  learn  from  studies  of  foehn  winds  where  no  such 
extended  snow-ice  surfaces  are  to  be  found,  that  this  expla- 
nation has  been  offered,  and  that  they  are  now  believed  to  be 
due  to  refrigeration  by  contact  with  elevated  mountain  sur- 
faces. 

In  the  Bavarian  highlands  the  foehn  winds  are  found  to 
be  preceded  by  anticyclonic  conditions  and  a  very  stable 
stratification  of  the  atmosphere.  The  foehn  sets  in  earliest 
at  the  high  stations,  and  during  its  descent  to  lower  levels 
reaches  stations  having  the  same  altitude  simultaneously, 
even  though  these  be  located  in  different  valleys.  Stagnant 
air  cooled  by  contact  with  the  mountain  sides  always  starts 
the  descending  currents.  The  cold  air  drains  away  to  lower 
levels,  and  sometimes  brings  about  a  reversal  of  normal 
conditions  so  that  the  higher  air  temperatures  are  at  the 
higher  levels.  When  the  currents  have  become  established, 
they  flow  down  the  valleys  like  rivers  and  the  curve  of  in- 
crease of  temperature  is  found  to  correspond  to  the  dry 
adiabatic  curve  for  air.29 

Recent  studies  of  the  warm  outflowing  currents  of  the 
Rocky  Mountain  regions  have  shown  that  these  flow  east- 
ward off  the  range  as  a  broad  sheet  which  has  been  followed 
for  many  hundreds  of  miles  in  a  north  and  south  direction.30 

Wind  Transportation  of  Snow.  —  For  the  Greenland  con- 
tinental glacier  it  has  been  shown  that  the  strong  winds 
are  probably  a  far  more  potent  factor  in  the  transportation 
of  the  snow  than  are  all  the  other  influences  combined.  The 
same  would  appear  to  be  no  less  true  of  the  Antarctic  con- 
tinent.31 During  strong  southerly  gales  the  snow  upon  the 


272         CHARACTERISTICS  OF  EXISTING  GLACIERS 

surface  is  picked  up  by  the  wind  and  the  air  is  filled  to  a 
height  dependent  upon  the  wind  velocity.  This  in  the  case 
of  moderate  winds  may  be  only  a  foot  or  two,  so  that  dogs 
would  be  submerged  in  it,  though  ponies  would  still  have 
their  heads  clear.  During  fierce  blizzards,  however,  the  air 
is  loaded  with  snow  to  a  much  greater  height.32 

The  strong  winds  of  the  region,  as  we  have  seen,  always 
blow  down  off  the  plateau  in  the  direction  of  the  steepest 
gradients.  The  southerly  blizzards  encountered  by  Shack- 
leton  near  the  end  of  his  southern  journey  entirely  swept 
away  all  surface  snow  of  recent  deposit,  leaving  for  the 
return  a  hard  and  white  snow  surface  resembling  Carrara 
marble.  Descending  the  Beardmore  outlet,  the  surface  for 
the  first  one  hundred  miles  he  likewise  found  swept  clean, 
but  the  lower  forty  miles  was  buried  deep  under  drift  snow.33 
Above  the  Backstairs  Passage  David  found  the  ice  surface 
similarly  hard  and  marble-like. 

Over  the  Nordenskiold  shelf-ice  tongue,  snow  is  carried 
from  the  southern  to  the  northern  margin,  where  it  builds  a 
great  ice-foot  which  the  sea-ice  pulls  away  in  sections  to 
form  a  high  cliff.  Within  a  zone  surrounding  the  rocky 
islands  off  the  coast  of  Antarctica,  ice-foot  or  fringing  glaciers 
are  developed  from  the  same  cause.  The  Ross  Barrier  and 
other  bodies  of  shelf-ice  are  built  higher,  and,  as  already 
explained,  doubtless  owe  their  origin  to  local  snow  deposit, 
probably  in  large  part  borne  from  long  distances  by  the  wind. 
The  inland-ice  of  Kaiser  Wilhelm  Land  is  swept  clear  of  snow 
by  the  southeast  storms,  and  the  snow  removed  is  probably 
lodged  farther  to  the  west,  where  it  forms  the  West-ice. 

As  upon  the  Greenland  continental  glacier,  so  here  in 
Antarctica,  the  resemblance  to  Sahara  conditions  is  most 
striking,  the  fine,  hard  snow  grains  driven  by  the  wind  be- 
having as  does  the  sand  of  the  desert.  Says  Gourdon: 34  — • 


NOURISHMENT  OF  ANTARCTIC   ICE   MASSES        273 

Such  snow  has  received  the  name  poudrin;  in  accumulating 
upon  the  surface  it  has  no  consistency  —  the  grains  remain  with- 
out cohesion.  The  foot  has  the  sensation  of  sinking  in  fine  sand. 
Certain  marches  reminded  me  of  nothing  so  much  as  of  those  which 
at  another  time  I  had  made  in  Southern  Tunis. 

Picked  up  by  the  wind  this  snowy  powder  is  the  chasse  neige, 
veritable  blinding  clouds  which  at  times  acquire  a  formidable 
violence ;  one  sees  them  rise  in  whirls  above  the  crests,  sweep  the 
white  plains  and  rob  the  glaciers  of  all  the  movable  portions.  A 
great  part  of  this  snow  is  borne  to  the  sea ;  another  part  accumu- 
lates in  long  undulations  called  sastrugi ;  another,  finally,  pro- 
tected behind  some  obstacle,  ice  or  rock,  is  piled  up  in  the  form  of 
dunes.  In  short,  this  snow  behaves  like  the  sand  of  the  desert, 
and,  further,  like  it,  though  of  less  intensity,  it  has  eolian  move- 
ments. 


FIG.  136.  —  The  lee  side  of  a  sand  dune  on  the  coast  of  northern  California.  Note 
the  resemblance  of  the  curve  of  profile  to  that  of  continental  glaciers  (after  a 
photograph  by  Fairbanks). 

Recognition  of  the  importance  of  wind  transportation  in 
connection  with  continental  glaciers  raises  the  question  as 


274        CHARACTERISTICS  OF   EXISTING  GLACIERS 

to  how  far  their  peculiar  marginal  sections  are  controlled 
by  this  factor.  There  is  evident  in  the  sections  across  the 
margin  of  the  inland-ice  an  approximation  to  a  regular  curve 
(see  Fig.  132).  The  resemblance  of  this  curve  to  the  curve 
of  profile  on  the  lee  side  of  sand  dunes  (see  Fig.  136)  is  most 
striking.  Fringing  glaciers  of  both  the  Arctic  and  Antarctic 
regions  are  in  reality  dunes  of  granular  sand  like  snow,  and 
it  seems  likely  that  the  margins  of  the  inland-ice  are  broadly 
moulded  by  this  process  (see  Fig.  137). 

"2000~NIncIe  -  _^--—  —  -  ca'1900m  —  —  —  _^~  -  STntfT2000  " 

-1500-f-^  -  ^^^^"  -  ^-^^^  -  -  --  j-1500  - 

-1000  lls/^  -  ^^-^  --  j-1000- 


.500  - 

Om 


FIG.  137.  —  Section  across  the  Vatnajokull  of  Iceland  (after  Spethmann  and 

Thoroddsen). 


The  relative  parts  played  by  wind  transportation  upon 
the  surface  and  by  ice  regelation  and  flow  beneath  it  are  yet 
to  be  determined.  The  sharp  contact  of  neves  now  with 
blue  glacier  ice  at  the  head  of  the  Ferrar  outlet  appears  to 
bear  upon  this  point. 

High  Level  Cirrus  Clouds  the  Source  of  Snow  in  the  Interior 
of  Antarctica.  —  It  has  heretofore  been  thought  open  to 
question  whether  within  the  interior  of  Antarctica  any  snow 
is  precipitated  in  the  ordinary  sense.  The  fact  that  the  winds 
capable  of  transporting  the  snow  all  move  outward  upon  the 
plateau  and  that  to  the  farthest  point  reached  by  Shackle- 
ton  what  appeared  to  be  new-fallen  snow  was  encountered, 
almost  makes  it  necessary  to  assume  that  even  there  snow 
reaches  the  surface  of  the  plateau  from  the  surrounding  air 
and  is  not  all  of  it  merely  lifted  and  again  deposited  by  the 
wind.  It  is,  however,  clear  that  no  moisture  can  there  be 
derived  from  surface  currents,  since  all  move  outward  from 
the  region.  The  only  possible  source  of  new  snow  is,  there- 


NOURISHMENT  OF  ANTARCTIC  ICE  MASSES        275 

fore,  the  high  level  currents,  which  from  cloud  studies,  as  well 
as  from  the  observations  of  Mt.  Erebus,  are  clearly  shown  to 
supply  the  air  of  the  Antarctic  anticyclones. 

As  already  stated,  the  dominant  surface  winds  upon  the 
continental  margins  come  from  the  south  and  southeast,  with 
the  easterly  component  larger  at  the  lower  latitudes  due  to 
deflection  by  earth  rotation.  The  upper  currents  come,  in 
general,  from  the  northwest  quadrant  and  are  more  curved  tow- 
ard the  south  as  they  pass  southward  over  the  Ross  Barrier. 

Over  the  ice  plateau  the  characteristic  clouds  which  were 
observed  are  the  high  broken  cirrus  and  cirro-stratus.35  At 
times  the  peculiar  "  polar  bands  "or  "  Noah's  Ark  "  clouds 
were  seen  stretching  across  the  sky  and  converging  at  oppo- 
site points  of  the  horizon,  the  direction  of  their  movement 
being  here  always  southerly.36  On  the  west  of  Ross  Sea  the 
direction  of  these  polar  bands  was  from  the  north-northeast  or 
northeast  curving  round  from  the  north.  This  is  not  in  accord- 
ance with  the  theory  of  the  polar  anticyclone,  but  conforms  to  that 
of  a  continental  (glacial)  anticyclone,  since  the  surface  currents 
on  the  plateau  in  this  vicinity  come  from  the  westerly  quarter. 

In  these  high  levels,  clouds  floating  at  an  altitude  certainly 
in  excess  of  14,000,  and  probably  25,000  feet,  the  moisture 
must  be  frozen,  since  the  temperature  of  air  ascending 
through  6000  feet  only  is  adiabatically  lowered  by  about 
35°  F.  There  is,  however,  the  probability  that  in  general  this 
snow  or  ice  is  adiabatically  melted  and  vaporized  during  its 
descent  to  the  plateau,  and  subsequently  congealed  as  it 
mixes  with  the  cold  air  above  the  plateau  surface.  This 
would  explain  the  clear  skies  which  are  so  general  over  both 
Greenland  and  Antarctica  during  snows  in  the  higher  levels. 
It  is  of  course  true  that  the  latent  heat  of  fusion  and 
vaporization  of  ice,  abstracted  as  it  is  from  the  air  during 
its  descent  within  the  eye  of  the  anticyclone,  will  counter- 
act to  some  extent  the  warming  adiabatic  effect;  and  it  is 


276        CHARACTERISTICS  OF  EXISTING  GLACIERS 

not  improbable  that  the  long  duration  of  Antarctic  blizzards 
and  their  somewhat  sudden  terminations  accompanied  by 
snowfall  are  explained  in  part  by  the  transformations  of 
latent  and  sensible  heat. 

Additional  evidence  for  the  continental  and  glacial  rather 
than  the  polar  nature  of  the  Antarctic  anticyclone  is  derived 
from  the  strong  blizzards  observed  at  the  British  winter 
quarters  on  McMurdo  Sound.  Whereas  the  lighter  gales  came 
from  the  southeast  and  indicate  a  control  by  local  conditions,37  a 
blizzard  of  the  first  magnitude  was  not  thus  influenced,  and  al- 
ways swept  down  from  the  southwest  —  that  is,  from  the  high 
plateau,  and  not  from  the  pole,  since  otherwise  the  earthys  rota- 
tion would  have  given  it  an  easterly  direction.  When  its 
powers  begin  to  wane,  it  is  once  more  controlled  by  local 
conditions  and  the  wind  again  comes  from  the  southeasterly 
quarter.38 

An  apparent  confirmation  of  this  theory  of  the  alimenta- 
tion of  inland-ice  masses  is  to  be  found  in  Nordenskjold's 
narrative  of  the  sledge  journey  across  Northeast  Land 
(Spitzbergen)  in  1873.  While  Nordenskjold  did  not  at  that 
early  day  and  on  the  basis  of  the  single  journey  discover 
the  important  law  of  atmospheric  circulation  above  an  in- 
land-ice mass,  which  the  subsequent  explorations,  particu- 
larly of  Peary,  Scott,  and  Shackleton,  have  revealed,  yet  the 
presence  there  of  essentially  the  same  conditions  is  probable 
from  his  narrative.39  The  fine,  hard  snow  was  found  to  be 
almost  constantly  in  motion  along  the  surface,  which  was 
glazed  and  polished  by  its  action.  Under  ordinary  circum- 
stances, this  stream  of  rounded  snow  grains  rose  a  few  feet 
only  into  the  air,  but  even  then  it  was  so  troublesome  as  to  be 
likened  to  the  desert  sand  in  the  Sahara. 

After  the  first  day  upon  the  inland-ice,  during  which  the 
weather  was  clear,  either  snow-storms  or  dense  snow  mists 
were  the  rule,  and  several  times  a  quite  remarkable  phenom- 


NOURISHMENT  OF  ANTARCTIC  ICE   MASSES        277 

enon  was  observed  which  we  may  best  describe  in  Norden- 
skjold's  own  words  as  rendered  by  Leslie  :  40  — 

During  our  journey  over  the  inland  ice,  we  several  times  had 
a  highly  peculiar  fall  of  - 

1.  Small,  round  snowflakes,  sometimes  resembling  stars,  of  a 
woolly  appearance. 

2.  Grains  falling  simultaneously,  of  about  the  same  size  as 
the  snowflakes,  but  formed  of  a  translucent,  irregular  ice  kernel, 
surrounded  by  a  layer  of  water,  which,  however,  froze  in  a  few 
moments  after  the  fall  of  ice,  and  in  a  short  time  covered  our  sledge- 
sail,  etc.,  with  a  thin  and  smooth  crust,  or  fastened  itself  to  our  hair 
and  clothes  as  small  translucent  ice-drops.     During  one  such  fall 
on  the  5th  June  there  were  seen  simultaneously  a  faint  halo  and  a 
common  rainbow,  the  temperature  being  4°  to  5°  C.  under  the 
freezing  point.     [See  Fig.  138.1 

We  have  thus  here  to  do  with  irregular  ice  grains  envel- 
oped in  water,  falling  in  sunlight  near  the  glacier  surface  in 
a  temperature  4  to  5  centigrade  degrees  below  the  freezing 
point,  and  in  association  with  freshly 
precipitated  felty  snow-flakes.  Since  all 
the  material  of  the  glacier  surface  is 
snow,  the  source  of  the  ice  kernels  must 
be  within  the  upper  atmospheric  regions. 
We  know  of  no  source  there  save  only 
the  ice  grains  composing  the  cirrus  FlG.  iss.  —  Section  of 
clouds.  The  water  envelope  about  the  one  of  the  irregular  ice 

A  .  grains     enveloped     in 

ice  kernels  would  be  explained  by  the       water  which  was  pre- 
adiabatic  rise  in  temperature  during  the       cipitated  together  with 

snow-flakes   upon    the 

descent  of  these  grains  to  the  plateau       iniand-ice  of  Northeast 


within  the  eye  of  the  anticvclone,  and       LarK|    <*?*?;   A-    E- 

Nordenskiold). 

the  sudden  subsequent  freezing  would 
be  explained  by  the  arrest  of  the  downward  motion  and 
the  mixing  with  cold  layers  of  air  lying  in  contact  with  the 
glacier.      The  associated  snow-flakes  would  be  derived  by 


278        CHARACTERISTICS  OF  EXISTING  GLACIERS 

similar  changes  of  temperature  from  those  smaller  ice 
grains  which  during  their  descent  to  the  plateau  had  been 
entirely  melted  and  vaporized,  as  well  as  from  the  vapor 
of  the  water  envelopes  about  the  ice  kernels.  It  will  be 
interesting  to  learn  when  the  central  areas  of  the  Greenland 
and  Antarctic  glaciers  have  been  similarly  penetrated, 
whether  a  like  phenomenon  is  characteristic  of  them.41  The 
much  higher  altitudes  and  the  lower  temperatures  make  it, 
however,  rather  unlikely.  While  it  thus  appears  to  be  true 
that  the  inland-ice  of  Northeast  Land  is  able  to  induce  a 
local  glacial  anticyclone  within  the  atmospheric  envelope, 
the  somewhat  smaller  ice  mass  of  the  Vatnajokull  in  Iceland 
produces  apparently  no  such  disturbance.42  This  is  proba- 
bly not  alone  to  be  explained  by  the  somewhat  smaller 
dimensions  of  the  Icelandic  ice  mass,  but  quite  as  much  by 
the  fact  that  it  is  near  the  centre  of  a  fixed  low  pressure  area 
of  the  atmosphere  with  disturbances  of  large  extent  and  of 
exceptional  violence.  The  problem  of  the  size  of  ice  cara- 
pace which  under  normal  conditions  is  just  able  to  induce  a 
local  anticyclone  within  the  atmosphere  is  one  of  great 
interest,  for  with  the  initiation  of  this  gas  engine  we  reach 
an  important  turning  point  in  the  processes  of  glacier  ali- 
mentation and  depletion. 

At  the  beginning  of  this  volume  it  was  stated  that  air  tem- 
perature has  come  to  be  recognized  as  the  chief  factor  in  the 
initiation  of  glaciation.  While  this  is  true,  the  factor  of 
temperature  loses  its  dominance  and  becomes  secondary  in 
importance  to  wind  currents  so  soon  as  the  local  anticyclone 
has  been  strongly  developed.  As  we  have  seen,  this  anti- 
cyclone not  only  puts  a  stop  to  the  nourishment  of  the  glacier 
by  moisture-laden  air  currents,  but,  in  addition,  it  constantly 
transports  the  snow  of  the  central  portion  to  the  margins. 
This  process  tends  to  reduce  the  altitude  of  the  central  por- 
tion of  the  mass  as  it  extends  the  margins.  With  a  continu- 


NOURISHMENT  OF  ANTARCTIC  ICE  MASSES        279 


ance  of  the  process,  the  vigorous  outward-blowing  currents 
of  the  anticyclone  extend  the  margins  toward  the  sea,  where- 
upon large  amounts  of  snow  are  there  deposited,  dissipated, 
and  consequently  lost  to  the  inland-ice.  Were  it  not  for  the 
fact  that  the  same  engine  pulls  down  the  ice  grains  in  the 
cirrus  cloud  masses  so  as  to  in  part  replace  its  earlier  nourish- 
ment by  the  snow  of  low-level  currents,  the  local  anticyclone 
must  quickly  induce  a  receding  hemicycle  of  glaciation,  re- 
sulting eventually  in  its  own  extinction.  It  is,  in  fact,  quite 
possible  that  a  limit  is  set  upon  glacier  size  by  the  refrigerated 
air  engine  thus 
brought  into  exist- 
ence, and  that  the 
great  Antarctic 
glacier,  now  in  a 
waning  stage,  is 
an  illustration  of 
this  fact. 

The  warming  of 
the  air  observed 
toward  the  close 
of  an  Antarctic 
blizzard,  and  the 
appearance  at  the 

rr»       fiTYiA    nf    tViP  FlG'  139-~  Sketch  map  showing  the  glaciated  and  the 

higher  non-glaciated  surfaces  of  the  rock  masses  which 

SOft       and       newly       protrude  through  the  ice  in  the  vicinity  of  McMurdo 

fallen    snow    in     Sound  (after  Ferrar)' 

place  of  the  lifted  and  driven  snow  of  the  earlier  stages, 
both  testify  to  the  existence  of  the  system  of  currents 
above  described.  Thus  an  adequate  explanation  is  found 
for  the  disappearance  of  moisture  congealed  in  the  ice 
grains  of  cirrus  clouds. 

Former  Extent  of  Antarctic  Glaciation.  —  Studies  of  Green- 
landic  and  Antarctic  glaciation  alike  show  that  we  live  in  a 


SKETCH  MAP  or  Ice  DISTRIBUTION 

O     S 
E 


280         CHARACTERISTICS  OF  EXISTING  GLACIERS 

receding  hemicycle  of  glaciation.  According  to  Scott  the 
surface  of  the  great  inland-ice  mass  of  Victoria  Land  was 
once  from  400  to  500  feet  above  its  present  level.43  The 
Ross  Barrier  has  been  at  least  800  feet  higher  than  now,  since 
Dr.  Wilson  discovered  moraines  on  the  slopes  of  Mt.  Terror 
at  that  altitude  (see  Fig.  139).  The  barrier  must,  therefore, 
have  been  aground,  and  in  the  view  of  Scott,  it  once  filled  all 
the  Ross  Sea  as  far  out  as  Cape  Adare.  The  Bellany  Islands, 
much  farther  out  and  near  the  Antarctic  Circle,  are  more 
heavily  glaciated  than  is  Victoria  Land.  Since  1840,  when 
Ross  sailed  along  its  edge,  the  Ross  Barrier  has  receded  in 
places  a  distance  of  from  twenty  to  thirty  miles  (see  Fig.  113, 
p.  217).  The  Nordenskjold  shelf-ice  tongue  and  the  shelf- 
ice  of  Lady  Newnes  Bay  are  remnants  of  the  older  shelf-ice 
of  Ross  Sea  and  are  now  no  longer  adequately  nourished. 
The  mountain  glaciers  which  now  lie  on  the  east  slope  of  the 
mountain  rampart  of  Victoria  Land  indicate  clearly  that  they 
were  once  much  more  important  than  now.  Most  interest- 
ing of  all  are  the  ice  slabs  —  dead  piedmont  aprons  of  which 
the  feeders  have  disappeared.44 

To-day  it  is  highly  probable  that  far  more  snow  is  blown 
from  the  borders  of  the  continent  out  upon  the  sea-ice,  and 
hence  eventually  melted  in  the  water,  than  falls  upon  the  con- 
tinent and  its  shelf-ice  margin.  The  recession  is  to-day  in 
progress. 

On1  the  summit  of  the  Gaussberg  in  Kaiser  Wilhelm  Land, 
and  at  a  height  of  350  metres  (about  1140  feet)  above  the 
surface  of  the  surrounding  inland-ice,  erratic  blocks  of  gneiss 
were  found,  from  which  we  conclude  that  this  mountain  was 
once  entirely  submerged  beneath  the  inland-ice.45 

In  Belgica  Strait  (Gerlache  Channel)  of  West  Antarctica  in 
the  low  latitude  of  64°  S.  are  evidences  that  this  great  trench, 
fully  ten  miles  in  width,  was  once  completely  filled  by  a  great 
glacier  tongue  which  pushed  westward  into  the  Pacific.  The 


NOURISHMENT  OF  ANTARCTIC  ICE  MASSES        281 

lateral  moraines  of  this  ice  mass,  fifteen  to  twenty  feet  in 
height,  are  found  to-day  between  sixty-five  and  eighty  feet 
above  the  sea  level,  and  the  depth  of  the  channel  is  in  the 
neighborhood  of  2000  feet.46  Roches  montonnees  and  erratic 
boulders  found  upon  the  islands  of  the  Palmer  archipelago  to 
the  west  of  Belgica  Strait  afford  further  confirmation  of  the 
once  much  greater  extension  of  the  ice.  Other  data  from 
the  same  region  have  been  furnished  by  J.  G.  Andersson,47 
Otto  Nordenskjold  48  and  Gourdon.49  The  last-mentioned 
observer  is,  however,  of  the  opinion  that  the  present  rate  of 
recession  as  estimated  from  the  retreat  of  the  Ross  Barrier 
since  1840  has  been  given  too  much  weight.  That  the  pres- 
ent is,  however,  a  hemicycle  of  recession,  all  observers  are 
agreed. 

There  is  an  interesting  theoretical  problem  connected 
with  a  possible  future  extinction  of  the  Greenland  and 
Antarctic  continental  glaciers.  For  the  latter,  at  least,  the 
dimensions  of  the  superimposed  fixed  anticyclone  are  such 
that  the  highest  surface  of  the  snow-ice  dome  may  be  re- 
garded as  in  some  sense  an  eccentric  earth  pole  in  the 
wind  system  comparable  to  one  of  the  eccentric  magnetic 
poles.  The  high-level  air  currents  traveling  as  anti-trades 
are  at  this  point  drawn  down  to  the  surface  from  all  sides 
and  here  begin  their  return  journey  equatorward  as  sur- 
face currents.  Were  the  glacier  removed  entirely,  certain 
changes  in  the  wind  system  of  this  part  of  the  globe  would 
certainly  be  brought  about.  The  glacial  studies  herein  set 
.forth  show  quite  conclusively  that  it  is  the  dome-like  sur- 
face of  the  snow-ice  mass  with  its  universal  outward  grades 
always  increasing  in  value  toward  the  periphery,  quite  as 
much  as  its  refrigerating  property,  that  is  responsible  for 
the  vigor  of  the  glacial  anticyclone. 

We  are  still  without  knowledge  concerning  the  elevations 
or  the  configuration  of  the  underlying  Antarctic  basement, 


282         CHARACTERISTICS  OF  EXISTING  GLACIERS 

though  well  convinced  that  it  must  constitute  an  upland 
of  some  sort.  The  studies  of  v.  Ficker50  in  the  Eastern  Alps 
and  of  Bigelow  and  others  in  the  American  Cordillera, 
indicate  that  on  bare  mountain  slopes  there  is  at  times  a 
sliding  off  of  refrigerated  surface  air  under  essentially 
anticyclonic  conditions.  It  seems  likely,  therefore,  that  a 
continental  anticyclone  would  persist  over  an  outward  slop- 
ing Antarctic  continent  after  the  total  extinction  of  the  ice 
mass,  even  though  greatly  reduced  in  vigor. 

REFERENCES 

1  Proc.  Am.  Phil  Soc.,  vol.  49,  pp.  96-110. 

2  Racovitza,  I.e.,  p.  416. 

3  Arctowski,  in  "Through  the  First  Antarctic  Night,"  p.  431. 

4  Borchgrevink,  I.e.,  p.  305. 

5  E.  Gourdon,  in  J.  Charcot,  Expedition  Antarctique  Frangaise  (1903- 
1905),  Geographic  physique,  glaciologie,  petrographie,  Paris,    1908,  pp. 
71,  74. 

6  Mawson,  I.e.,  pp.  335-336. 

7  David,  Narrative  in  Shackleton's  "Heart  of  the  Antarctic,"  vol.  2, 
pp. 178-179. 

8  Scott,  I.e.,  vol.  2. 

9  E.  von  Drygalski,  "  Zum  Kontinent,  etc.,"  I.e.,  p.  394. 

10  David  and  Adams,  Meteorology  in  Shackleton's  "Heart  of  the  Ant- 
arctic," vol.  2,  p.  377. 

,  u  Arctowski,  in  Cook's  "Through  the  First  Antarctic  Night,"  pp.  429- 
431. 

12Bernacchi,  in  Borchgrevink' s  "First  on  the  Antarctic  Continent,'' 
p.  306. 

13  C.  W.  Royds,  "  On  the  Meteorology  of  the  part  of  the  Antarctic 
regions  where  the  '  Discovery '  wintered,"  Geogr.  Jour.,  vol.  25,  1905,  pp. 
387-392. 

14  David  and  Adams,  I.e.,  pp.  378-379. 

15  E.  von  Drygalski,  "  Zum  Kontinent,"  I.e.,  p.  268. 

16  Reprinted  in  Smithsonian  Report  for  1893,  1894,  pp.  353-373. 

17  Wm.  Ferrel,  "A  popular  treatise  on  the  winds,"  New  York,  1889. 

18  Wm.  M.  Davis,  "Elementary  Meteorology,"  Boston,  1894,  pp.  101, 
103-104,  110-111. 

19  A.  Buchan,  Smithsonian  Report  for  1897,  1898,  pp.  429-432. 

20  L.  Bernacchi,  "To  the  South  Polar  Regions,"  London,  1901,  pp.  294- 
295. 

21  Shackleton,  vol.  2,  p.  18. 

22  Proc.  Am.  Phil.  Soc.,  vol.  49,  pp.  99-104. 


NOURISHMENT  OF  ANTARCTIC  ICE  MASSES        283 

23  David,  Narrative,  pp.  176-184. 

24  Shackleton,  I.e.,  vol.  1,  pp.  341-348. 

25  David,  I.e.,  pp.  381-383. 

26  E.  von  Drygalski,  "  Zum  Kontinent,"  pp.  418-419. 

27  David,  I.e.,  p.  164. 

28  O.  Nordenskiold,  "  Ueber  die  Natur  des  West-Antarktisclien  Eisre- 
gionen,"  Zeit.  d.  Gesell.  f.  Erdkunde  z.  Berlin,  1908,  p.  616. 

29  N.  v.  Ficker,  "  Innsbrucker  Fohnstudien,  IV;  Weitere  Beitrage  zur 
Dynamik  der  Fohns,"  Holder,  Vienna,  1910,  pp.   37-38.     (Reviewed  in 
Nature  of  September  22,  1910,  pp.  368-369.) 

30  Science,  N.S.,  vol.  32,  Oct.  7,  1910,  p.  460. 

31  See  among  others :    Royds,  Geogr.  Jour.,  vol.  25,  1905,  p.  387 ;     O. 
Nordenskiold,  Zeit.  f.  Gletscherk.,  vol.  3,  1909,  p.  325. 

32  "The  air  is  entirely  filled  with  drifting  snow,  which  strikes  you  like 
a  sand-blast.     You  can  not  face  it  but  have  to  stumble  on  to  wherever 
you  may  be  going  with  your  head  down  and  arms  protecting  your  face, 
and  even  could  you  face  it,  you  are  not  able  to  see  a  yard  all  around  you.'* 
(Lieut.  Royds,  in  Geogr.  Jour.,  vol.  25,  1905,  p.  389.) 

"Nothing  more  appalling  than  these  frightful  winds,  accompanied  by 
tons  of  drift  snow  from  the  mountains  above,  can  be  imagined."  (Ber- 
nacchi  in  Borchgrevink,  I.e.,  p.  306.) 

"During  snow  storms  it  was  characteristic  that  the  snow  did  not  drive 
high.  The  masts  of  the  'Gauss'  were  frequently  free,  while  the  snow 
below  was  so  thick  that  nothing  could  be  seen."  (E.  von  Drygalski, 
"Zum  Kontinent,  etc.,"  p.  372.) 

"Nothing  is  more  trying  in  the  torment  than  this  powder  of  murderous 
crystals  which  whip  the  face  and  eyes  and  prevent  one  from  keeping  his 
direction.  Walking  is,  therefore,  at  times  impossible  and  the  traveller 
must  bury  himself  in  a  hole  in  the  snow  until  the  blizzard  is  over."  (E. 
Gourdon,  in  Charcot,  Expedition  Antarctique  Franc,aise,  1903-1905,  p.  74.) 

33  Shackleton,  vol.  2,  p.  19. 

34  Gourdon,  I.e.,  pp.  74-75. 

35  Royal  Soc.,   National    Antarctic   Expedition,   1901-1904.      Album  of 
photographs  and  sketches.     Description  of  Plate  155.     See  also  Racovitza, 
I.e.,  p.  416;  David  and  Adams,  I.e.,  p.  379;  David,  Narrative,  I.e.,  p.  91. 

36  David,  Narrative,  I.e.,  pp.  91,  168,  171,  175. 

37  The  winter  quarters  were  located  in  a  gully  or  "gap"  running  down 
from  the  barrier  surface  toward  the  sound  in  a  direction  from   southeast 
to  northwest.     (Royds,  I.e.,  p.  387.)     (See  fig.  139.) 

38  David  and  Adams,  I.e.,  pp.  379-383. 

39  A.  E.  Nordenskjold,  "  Die  Schlittenfahrt  der  schwedischen  Expedition 
im  nordostlichen  Theile  von  Spitzbergen,  24  April-15  Juni  1873,"   Pet. 
Mitt.,  vol.  19,  1873,  pp.  451-452.     Also  A.  Leslie,  "  The  Arctic  Voyages 
of   Adolf   Erik  Nordenskjold   1858-1879,"  with  illustrations  and  maps, 
London,  1879,  p.  257.     Also  A.  E.  Nordenskjold,  "  Redogorelse  for  den 
svenska  polarexpeditionen  ar    1872-1873,"    Bihang  till  K.  Svenska  Vet. 
'Akad.  Handlingar,  vol.  2,  no.  18,  1873,  pp.  1-132,  map  and  plate. 

40  A.  Leslie,  I.e. 


284         CHARACTERISTICS  OF  EXISTING  GLACIERS 

41  Shackleton's  journey  has  made  clear  that  the  boss  of  the  ice  plateau 
is  far  to  the  southwest  of  his  route. 

42  Personal  communication  from  Dr.  Th.  Thoroddsen. 

43  Scott,  vol.  2,  p.  423. 

44  Scott,  I.e.,  vol.  2,  pp.  422-425. 

45  E.  von  Drygalski,  Zeit.  f.  Gletscherk.,  I.e.,  p.  311.     Also  Philippi,  I.e., 
p.  7. 

46  H.  Arctowski,  "  The  Antarctic  voyage  of  the  'Belgica  '  during  the  years 
1897,  1898,  1899,"  Geogr.  Jour.,  vol.  18,  1901,  pp.  372-373. 

47  J.  G.  Andersson,  Bull.  Geol  Inst.  Upsala,  vol.  7,  1906,  pp.  53-57. 

48  O.  Nordenskiold,  Zeit.  f.  Gletscherk.,  vol.  3,  1909,  pp.  329-331. 

49  Gourdon,  I.e.  (1908),  pp.  116-121. 
^VonFicker,  I.e. 


AFTERWORD 

The  Two  Contrasted  Glacier  Types.  —  We  have  seen  that 
existing  glaciers  illustrate  two  widely  different  types  —  in- 
land-ice and  mountain  glaciers  —  with  the  small  ice-caps  in 
an  intermediate  and  transitional  position.  As  regards  the 
inland-ice,  the  Arctic  and  Antarctic  continental  glaciers  dif- 
fer mainly  in  degree ;  the  smaller  Arctic  form  being  entirely 
restricted  to  the  land  area,  whereas  the  Antarctic  ice-mass 
being  more  amply  nourished  is  locally  extended  by  a  mar- 
ginal terrace  floating  upon  the  sea.  Similarly  mountain 
glaciers  on  the  basis  of  their  alimentation  fall  naturally  into 
a  series  of  sub-types  ranging  on  the  one  hand  from  those 
which  spread  out  beyond  the  margin  of  the  upland  —  the 
piedmont  glacier  —  to  those  puny  forms  which  in  the  last 
stage  of  a  progressive  extinction  are  crowded  hard  against 
the  mountain  summits. 

Physiographic  Form.  —  As  regards  their  physiographic 
form  the  inland-ice  masses  adhere  to  a  definite  model  --a 
flat  dome  which  in  the  case  of  the  Antarctic  example  is  ex- 
tended by  a  lower  marginal  terrace  of  shelf  ice.  The  moun- 
tain glaciers,  on  the  other  hand,  conform  to  no  regular  model, 
but  have  a  relief  directly  determined  by  the  forms  of  the  sup- 
porting upland.  In  respect  to  form,  the  ice-cap  is  allied  to 
the  inland-ice,  having,  in  common  with  it,  small  irregularities 
in  the  surface  of  its  supporting  base  if  these  be  but  compared 
to  its  general  dimensions. 

285 


286         CHARACTERISTICS  OF  EXISTING  GLACIERS 

Denuding  Processes.  —  As  concerns  denuding  processes 
mountain  glaciers  are  in  common  with  inland-ice  character- 
ized by  the  capacity  to  lower  the  level  of  their  beds  through 
the  operation  of  the  processes  of  abrasion  and  plucking ;  but 
they  have  in  addition  the  power  to  denude  rapidly  by  cirque 
recession  —  extraordinarily  rapid  sapping  through  daily 
summer  frost  work  at  the  base  of  the  bergschrund.  Whereas 
inland-ice  reduces  the  irregularities  and  softens  the  outlines 
of  its  rock  bed,  mountain  glaciers  by  contrast  increase  the 
accent  of  the  relief,  and,  in  fact,  develop  a  more  sharply 
rugged  topography  than  does  any  other  known  geological 
process.  In  respect  to  denudation,  ice-caps  are  intermediate 
between  the  two  main  glacier  types.  While  their  main  deg- 
radational  process  is  apparently  abrasion  (plate  34  A)  they 
may,  when  aided  by  uplift  of  the  land  under  specially 
favorable  conditions,  develop  the  sharply  peaked  mountains 
known  as  tinds.  Unlike  the  peaks  carved  by  mountain 
glaciers,  these  sharp  peaks  are  developed  not  above  the 
higher  but  near  the  lower  ice  levels  (plate  34  B). 

Alimentation. — In  respect  to  nourishing  processes  the  two 
main  glacier  types  are  no  less  sharply  differentiated.  The 
ice-caps,  which  in  their  physiographic  form  are  allied  to  the 
inland-ice,  are  here  no  less  clearly  to  be  classed  with  moun- 
tain glaciers. 

Mountain  glaciers  are  nourished  by  moisture-laden  surface 
currents  of  air,  which  encountering  an  upland  area  are  forced 
to  rise,  and  are  thereby  cooled  adiabatically  and  by  contact 
with  the  upland,  so  that  their  burden  is  deposited  in  the  form 
of  snow.  Inland-ice,  on  the  contrary,  if  we  neglect  for  the 
moment  the  marginal  terrace  sometimes  present,  appears  to 
be  regularly  fed  from  high-level  currents  through  the  opera- 
tion of  a  refrigerating  air  engine  of  which  the  ice  mass  and  its 
atmospheric  cover  are  the  essential  parts.  : 

Through  the  rhythmic  action  of  this  engine  the  congealed 


PLATE  34. 


A.   View  of  the  high  surfaces  of  the  Jotunheim  from  the  Galdho,  showing  effect 
of  abrasion  beneath  ice-cap  glaciers  (after  Fritz  Machacek). 


B.  The  Maelkevoldsbrae  of  the  Jostefjelcl,  showing  the  development  of  tinds  about 
the  borders  of  a  Norwegian  ice-cap  through  the  erosional  work  of  outlet  glaciers 
(after  Fritz  Machacek). 


AFTERWORD  287 

moisture  derived  from  the  ocean  surface  within  moderate  or 
low  latitudes  and  carried  to  the  polar  region  in  the  high  level 
cirrus  clouds,  is  pulled  down  to  the  surface  of  the  glacier  in  the 
eye  of  a  great  glacial  anticyclone  which  is  centred  above  it. 
During  their  descent  from  high  levels  the  ice  grains  of  the 
clouds  are  melted  and  vaporized  by  adiabatic  warming,  and 
on  reaching  the  cold  surface  layer  of  air  next  the  ice,  are 
quickly  congealed  to  form  flakes  of  fresh  snow.  The  progres- 
sive warming  of  the  air  adiabatically  both  during  its  descent 
to  the  central  area  of  the  ice  mass  and  on  the  further  slide  out- 
ward to  the  peripheral  portions,  gradually  damps  and  eventu- 
ally stops  the  sliding  centrifugal  motion  of  the  surface  air- 
layer.  Thus  the  engine  comes  to  rest  or,  as  we  may  say, 
has  reached  the  end  of  its  stroke.  The  great  calm  which  en- 
sues allows  heat  to  be  again  slowly  abstracted  from  the  sur- 
face layer  of  air,  thereby  lowering  its  temperature  and  raising 
its  density  until  gravity  again  starts  the  engine,  which  now 
acquires  the  steadily  accelerating  velocity  characteristic  of 
bodies  sliding  on  inclined  planes.  The  tempest  which  is 
eventually  engendered  is  succeeded  by  a  rapid  rise  of  air 
temperature,  a  fall  of  fresh  snow,  and  another  stopping  of  the 
engine. 

The  fierce  violence  of  the  surface  air  currents  when  at  their 
maximum,  and  the  fall  of  the  snow  for  the  most  part  as  the 
engine  is  slowing  down,  together  make  of  this  glacial  anti- 
cyclone a  gigantic  snow  broom.  The  snow  deposited  as  it 
were  between  strokes  of  the  engine  is  by  the  next  sweep  of 
the  broom  brushed  largely  clear  from  all  central  portions  of 
the  glacier,  and  the  sweepings  are  deposited  near  and  about 
the  margins  of  the  mass  (see  Figure  140).  Since  the  con- 
tinental glacier  must  grow  during  the  advancing  hemicycle 
in  a  vertical  as  well  as  in  a  horizontal  direction,  there  must 
be  accretions  of  snow  upon  the  central  areas,  which  layers 
adhere  to  the  surface  so  as  not  to  be  removed  by  the 


288         CHARACTERISTICS  OF  EXISTING  GLACIERS 

rhythmic  engine  strokes.  Thus  are  produced  the  alternat- 
ing layers  of  incoherent  and  marble-like  snow  which  the 
crude  sections  of  the  surface  material  have  revealed.  We 


A    N  T  I  c         C  L  O.N 


FIG.  140.  —  Diagram  to  illustrate  the  growth  of  an  inland-ice  mass  through  the 
rhythmic  action  of  the  anticyclonic  air  engine. 

are  still  without  sufficient  knowledge  of  the  conditions 
which  give  rise  to  the  coherent  layers.  In  this  manner,  then, 
the  great  glacier  is  enlarged  and  shaped  through  periodic 
deposit  of  snow  in  successive  layers  upon  its  surface  but 
especially  by  more  frequent  deposit  of  sweepings  about  its 
margin.  This  process  plays  no  part  in  the  shaping  of 
mountain  glaciers. 

The  marginal  shelf  ice  appears  to  be  in  some  cases  at  least 
partially  nourished  by  the  overflow  of  glacier  ice  from  the 
neighboring  continental  area,  but  more  largely  it  is  fed 
through  the  continued  thickening  of  field  ice  —  the  frozen 
sea  surface  —  by  deposits  of  precipitated  snow  upon  its  sur- 
face. To  this  precipitated  snow  there  is  added  a  portion  of 
the  sweepings  carried  outward  from  the  surface  of  the  inland- 
ice.  That  portion  of  the  nourishment  which  is  derived  from 
glacier  overflow  at  its  inner  margin,  becomes  covered  by  the 
surface  deposits,  and  so  is  segregated  toward  its  lower  and 
inner  margins. 

The  formation  of  shelf  ice  is  greatly  favored  in  more  or  less 
sheltered  bights  from  which  the  sea  ice  is  less  easily  dislodged 
and  hence  does  not  take  part  in  the  annual  drift  of  the  pack 
toward  lower  latitudes.  Further  it  is  locally  favored  by  the 
stranding  or  freezing  into  the  sea  ice  of  a  fleet  of  icebergs 


AFTERWORD  289 

from  the  areas  of  inland-ice;  since  these  furnish  lanes  be- 
tween them  within  which  snow  sweepings  are  more  easily 
caught  and  retained. 

Marginal  Contours.  —  As  concerns  the  moulding  of  surface 
contours  at  the  glacier  margin,  the  determining  factors  in  the 
case  of  mountain  glaciers  seem  to  be  an  upturning  of  the  ice 
layers  in  this  region  and  surface  ablation  or  melting.  In  the 
case  of  inland-ice  the  important  factor  is  the  deposition  upon 
the  surface  of  snow  borne  by  the  wind  from  the  interior  of  the 
mass. 


INDEX 


Aarschlucht  near  Meiringen,  63. 

Ablation,  on  Greenland  glacier,  162. 

Accordance,  of  side  valleys,  cause  of,  67  ; 
of  summit  levels,  31. 

Adams,  Lieutenant,  cited,  282. 

Adelie  Land,  193. 

Adiabatic  refrigeration  of  air,  36,  150. 

Adiabatic  warming  of  air,  during  Ant- 
arctic blizzard,  269. 

Admiralty  Range,  193,  253. 

Advancing  hemicycle  of  glaciation,  6. 

Agassiz,  Louis,  cited,  3,  10,  167. 

Aiguille  type  of  mountain  ridge,  32. 

Air  circulation  over  Greenland  glacier, 
146. 

Air,  humidity  of,  in  Antarctica,  262 ;  in 
Greenland,  145-146. 

Air  temperatures,  relation  to  glaciation, 
4,  278 ;  over  inland-ice  of  Greenland, 
145. 

Alaska,  icebergs  of,  178. 

Albs,  53,  64. 

Alexander  I  Land,  211. 

Alimentation,  of  glaciers,  286  ;  of  Green- 
land glacier,  131,  143;  of  mountain 
glaciers  in  polar  regions,  260. 

Alpine  glaciers,  52  ;    of  Antarctica,  259. 

Amundsen,  Roald,  cited,  206,  211,  213. 

Ancestry  of  glacial  theories,  1. 

Andersson,  J.  Gunnar,  cited,  96,  141, 
210,  211,  243,  252,  281,  284. 

"Antarctica,"  crushing  of,  in  pack  ice, 
205  ;  sinking  in  pack  ice,  view  of,  205. 

Antarctica,  exploration  of,  190 ;  maps 
of,  194,  195  ;  rock  basement  of,  281. 

Antarctic  glacier,  larger  than  land  base, 
187 ;  where  unconfined,  245 ;  where 
unconfined,  view  from  sea,  246. 

Antarctic  region,  characterized,  98 ; 
climatic  symmetry  of,  99. 

Anticyclone,  glacial,  essentials  of,  148. 

Apron,  outwash,  87. 

Aprons,  ice,  below  outlets,  257 ;  of  shelf- 
ice  tongues,  234. 

Arctic  glacier  type,  97. 

Arctic  region,  characterized,  98  ;  climatic 
asymmetry  of,  99 ;  contrasted  with 
Antarctic,  186. 


Arctowski,  Henryk,  cited,  189,  197,  198, 

202,  210,  211,  212,  213,  238,  243,  264, 

282,  284. 
Arete,  32. 
Asakak  glacier  outlet  (Greenland),  125, 

134. 

Asulkan  glacier,  54,  55. 
Asymmetry  of   Greenland  glacier,    131, 

146. 
Atmospheric  depression,  fixed  areas  of, 

99. 

Atwood,  W.  W.,  cited,  26,  39,  60. 
Austmann  valley,   Greenland,  moraines 

of,  138. 

Backstairs  passage,  Victoria  Land,  254- 
272. 

Baffin  Land,  map  of,  117. 

Baffin's  Bay,  currents  in,  162. 

Bagnoires,  166. 

Baird  glacier,  Alaska,  46. 

Balch,  E.  S.,  cited,  210. 

Baltoro  glacier,  47,  50. 

Barchans,  of  snow,  156. 

Barrier-ice.     See  Shelf-ice. 

Basin,  tongue-like,  before  mountain 
front,  83. 

Basins  of  exudation  above  outlets,  Green- 
land glacier,  132. 

Beardmore  outlet,  223,  233,  253,  254, 
256,  257,  272 ;  map  of,  258. 

"Belgica"  expedition,  189,  191,  196,  197, 
200,  203,  206,  262,  265. 

Belgica  Strait,  former  glaciation  of, 
280. 

Belleny  Islands,  192,  209,  280,  pi.  27. 

Benard,  Charles,  cited,  118. 

Benedict  glacier,  169,  pi.  25. 

Bergen  railway,  Norway,  melting  of 
snow,  on,  166,  176. 

Bergschrund,  15,  61 ;  explored  by  John- 
son, 16 ;  in  relation  to  cirque,  14 ; 
time  of  its  appearance,  22. 

Bering  glacier,  Alaska,  43. 

Bernacchi,  L.,  cited,  189,  210,  212,  242, 
264,  265,  282,  283. 

Biafo  glacier,  47. 

Bigelow,  F.  H.,  cited,  282. 


291 


292 


INDEX 


Bighorn  Mountains,  cirque  cutting  in,  19. 

Birth  of  tabular  bergs,  235. 

Biscoe,  John,  cited,  192,  196,  215. 

Bishops  glacier,  Frontispiece. 

Blackwelder,  E.,  cited,  56. 

Blizzards,    Antarctic,     264,    268,     272; 

duration  of,  in  relation  to  latent  heat 

transformation,     276 ;      sequence     of 

events  during,   269 ;    termination  of, 

276. 

Blue  glacier,  259. 

Bonney,  T.  G.,  cited,  12,  15,  22,  23. 
Borchgrevink,  C.  E.,  cited,  191,  204,  211, 

216,  230,  231,  242,  282,  283. 
Border  lakes,  83. 
Bouvet  Island,  209,  pi.  28. 
Braided    streams,    flowing   from   glacier 

front,  85-86. 

"Break  up"  of  sea-ice,  206. 
Brooks,  Alfred  H.,  cited,  56,  57. 
Brown,  et  al.  (of  "Scotia"  expedition), 

cited,  211,  242,  252. 

Bruce,  W.  S.,  cited,  189,  193,  212,  216. 
Bruckner,  E.,  cited,  10,  11,  40,  56,  60, 

62,  69,  84,  85,  96,  212. 
Bryant  glacier,  pi.  22. 
Buchan,  A.,  cited,  100,  265,  282. 
Butler,  B.  F.,  cited,  58,  185. 

Calhoun,  F.  H.  H.,  cited,  56,  88,  96. 
"Canals,"  on  inland-ice  of  North  East 

Land,  115;    view  of,  114;    hypotheti- 
cal section  of,  115. 
Cape  Adair,  189f  191,  199,  223,  240,  249, 

262,  264. 

Cape  Armitage,  189,  190. 
Cape  Carr,  192. 
Cape  Royds,  220,  223,  264. 
Capps,  Stephen  R.,  Jr.,  cited,  96. 
Carbon  dioxide,  content  of,  in  air  over 

Greenland  glacier,  145. 
Cascade  stairway,  59. 
Case,  E.  C.,  cited,  137. 
Cauldron  glaciers,  51. 
"Challenger"  expedition,  190,  197,  198, 

211,  212,  237,  241. 
Chamberlin,  T.  C.,  cited,  12,  22,  56,  137, 

138,  139,  140,  141,  142,  153,  160,  170, 

176,  209. 
Characteristic  profiles,  from  high  latitude 

glaciation,  74. 
Characteristic   section,    from   successive 

landslides  in  canyon,  92. 
Charcot,  J.,  191,211,  212,  252,  282. 
Charpentier,  Jean  de,  cited,  3. 
Chasse  neige,  273. 
Childs  glacier,  Alaska,  45. 
"Chimneys,"  30. 
"Chinese  Wall,"  on  Grinnell  Land,  116, 

128;  view  of,  116. 


Chistochina  glacier,  48. 

Chun,  cited,  213. 

Cirque,  definition,  10 ;  figure  after 
Richter,  14;  form  of,  in  different 
stages,  31 ;  its  initiation,  18 ;  its  re- 
cession, 12  ;  relation  to  Bergschrund, 
14. 

Cirques,  in  Victoria  Land,  259 ;  loca- 
tion of,  in  early  stages,  32 ;  maturity 
of,  29  ;  multiple,  30  ;  nourishment  of, 
by  snow,  31 ;  on  lee  side  only  of  moun- 
tain range  in  Colorado,  28  ;  rock  flows 
from  abandoned,  94. 

Cirrus  clouds,  nature  of  moisture  in, 
275  ;  snow  of,  158 ;  source  of  Green- 
landic  snowfall,  158 ;  source  of  snow 
in  interior  of  Antarctica,  274. 

Cliff  glaciers,  54. 

Climatic  conditions,  affecting  nourish- 
ment of  Antarctic  ice  masses,  216. 

Clouds,  over  Greenland  ice,  type  of,  159 ; 
"Polar  bands"  of  Antarctica,  275. 

Coats  Land,  193,  195,  197,  216,  245,  270 ; 
view  of,  216. 

Col,  formed  by  intersection  of  cirques, 
34 ;  typical  example  from  Selkirks, 
pi.  9. 

Cols,  characteristic  high  levels  of,  35. 

Comb-ridges,  32. 

Conditions  which  bring  on  glaciation,  5. 

Continental  (glacial)  anticyclone  of  An- 
tarctica, 265,  266. 

Continental  glacier,  of  Greenland,  cross 
section  of ,  122;  physiography  of ,  119; 
of  Victoria  Land,  253. 

Continental  platform,  Antarctica,  196. 

Contrast  of  northern  and  southern  polar 
areas,  98. 

Convict  Lake,  view  of,  82. 

Conway,  Sir  Martin.  See  W.  M.  Con- 
way. 

Conway,  W.  M.,  cited,  57,  98,  111,  112, 
117,  118. 

Cook,  Captain  James,  cited,  190,  192, 
196,  215. 

Cornell  glacier,  172,  pi.  24,  pi.  26. 

Cornish,  Vaughan,  cited,  155,  157,  161. 

Corries,  of  Scottish  highlands,  34. 

Cracks,  tide,  208. 

Crevasses,  in  Greenland  glacier,  129  ;  in 
inland-ice  of  North  East  Land,  115; 
rectangular,  in  Antarctic  glacier,  247. 

"Cryaconite"  wells,  on  Antarctic  glacier, 
248. 

Cryohydrates,  from  sea-ice  formation, 
199. 

Cutting  effect,  of  drift  snow,  154. 

Cycle  of  glaciation,  6. 

Cyclonic  air  circulation,  over  south 
margin  of  Greenland  glacier,  149. 


INDEX 


293 


Dalagers  nunataks,  Greenland,  scape 
colks  at,  135 ;  map  of,  136. 

Daly,  R.  A.,  cited,  31,  40. 

Danco  Land,  211. 

Daubree,  A.,  cited,  201,  213,  236. 

David  outlet,  233,  254. 

David,  T.  W.  E.,  cited,  213,  242,  243, 
255,  260,  266,  267,  269,  270,  272,  282, 
283. 

Davidson  glacier,  Alaska,  45. 

Davis,  W.  M.,  cited,  6,  9,  11,  25,  39,  66, 
67,  265,  282. 

Dawson  glacier,  pi.  6. 

Delta,  in  ice-dammed  lake,  pi.  26. 

Dendritic  glaciers,  47. 

Denuding  processes,  of  glaciers,  286. 

Depletion,  of  glaciers,  special  causes  of, 
36  ;  of  Greenland  glacier,  from  surface 
melting,  162. 

Depot  "A,"  Victoria  Land,  222,  223. 

Deserts  and  inland-ice  compared,  150, 
272,  273-276. 

Devil's  Thumb,  Greenland,  glacier  mar- 
gin at,  126. 

Diagram,  of  shore  line  of  marginal  lakes, 
172 ;  to  illustrate  air  circulation  over 
Greenland  glacier,  146 ;  to  illustrate 
birth  of  icebergs  (Reid),  181 ;  to  illus- 
trate birth  of  icebergs  (Russell),  180; 
to  illustrate  differential  melting  about 
rock  fragments,  166,  167  ;  to  illustrate 
formation  of  col,  34 ;  to  illustrate 
formation  of  horns,  33  ;  to  illustrate 
formation  of  lakes  in  drift  ice,  202  ; 
to  illustrate  formation  of  zigzag  leads, 
202  ;  to  illustrate  growth  of  inland-ice 
mass,  288 ;  to  illustrate  regular  cracks 
in  drift  ice,  201 ;  showing  longitudinal 
section  of  glaciated  valley,  60 ;  show- 
ing manner  of  formation  of  "West 
ice,"  230 ;  showing  serial  subsurface 
temperatures  in  Greenland  glacier, 
164  ;  to^how  "biscuit  cutting"  effects, 
26. 

Differential  surface  melting  of  ice,  165. 

Di  Filippi,  Filippo,  cited,  40. 

Dimples,  above  outlets  of  Greenland 
glacier,  132  ;  on  Antarctic  glacier,  257 ; 
on  Greenland  ice  near  Disco  Bay,  134. 

Direction  of  nearest  land  determined  by 
winds  over  ice,  147. 

Dirk  Gerritz  Archipelago,  211. 

Dissection  of  upland,  by  mountain 
glaciers,  stages  of,  pi.  4. 

"Docks,"  in  North  East  Land,  116. 

Drainage,  on  Greenland  glacier,  170. 

Drift  ice,  pressures  in,  200. 

Drift  site,  in  Lapland,  figure  after  pho- 
tograph by  Von  Zahn,  21. 

Drift  sites,  in  Bighorn  Mountains,  19. 


Drift  snow,  over  Greenland  glacier,  151. 

Drumlins,  position  of,  in  site  of  ice  apron, 
83. 

Drygalski,  E.  v.,  cited,  11,  125,  131,  134, 
138,  141,  142,  146,  153,  160,  161,  162, 
163,  169,  174,  176,  177,  179,  183,  184, 
189,  191,  192,  193,  203,  210,  211,  227, 
228,  230,  239,  241,  242,  243,  244,  246, 
249,  250,  252,  270,  282,  283,  284. 

Drygalski  shelf-ice  tongue,  223,  231,  233, 
254,  270. 

Dugdale  glacier,  230,  231. 

Duke  of  the  Abruzzi,  cited,  106,  108, 
118. 

Dumond  d'Urville,  J.  S.  C.,  cited,  190, 
193,  210. 

Dunes,  snow,  274. 

Dusen,  P.,  cited,  124. 

Dust  wells,  166,  167. 

Ebeling,  Max,  cited,  118. 

Effects  of  wind  drift  on  snow  density, 
157. 

Ellesmere  Land,  inland-ice  of,  116;  map 
of,  115. 

Enderby  Land,  192,  195,  196,  215. 

Engell,  M.  C.,  cited,  179,  184,  185. 

Englacial  drainage,  on  Greenland  glacier, 
170. 

Englacial  streams,  Antarctica,  234. 

Environment,  importance  of  in  evolu- 
tion of  science,  2. 

Erebus,  Mount,  behavior  during  bliz- 
zard, 269,  275. 

Ericksen,  Mylius,  expedition  of,  in 
Greenland,  121. 

Ericksen 's  route  across  inland-ice  of 
northeast  Greenland  (map),  127. 

Erosion  by  drift  snow,  154,  155. 

Eskers,  87  ;   manner  of  formation  of,  88. 

Evaporation,  over  inland-ice  of  Green- 
land, 145. 

Exfoliation,  its  part  in  formation  of 
tinds,  79. 

Expanded-foot  glaciers,  45,  pi.  10. 

Experiments  in  glacier  motion,  137. 

Explorations,  Antarctic,  3. 

Fairbanks,  H.  W.,  cited,  82,  273. 

Features  within  marginal  zone  of  Green- 
land glacier,  129. 

Feeder  basins  (dimples)  on  Greenland 
ice,  134. 

Feilden,  H.  W.,  cited,  24,  71,  80. 

Ferrar  glacier,  253. 

Ferrar,  H.  T.,  cited,  212,  213,  242,  259, 
260,  279. 

Ferrel,  William,  cited,  265,  282. 

Ficker,  Heinrich  v.,  cited,  271,  282,  283, 
284. 


294 


INDEX 


Field-ice,  defined,  198 ;  manner  of  forma- 
tion of,  199. 

Filchner,  Wilhelm,  cited,  212. 

Fixed  areas  of  atmospheric  depression, 
99. 

Fjords  of  western  Norway,  73. 

Flatly  grooved  glacier  valleys,  72. 

Flimser  Bergstiirz,  93. 

Fluvio-glacial  deposits,  88 ;  of  Green- 
land, 142. 

Foehn  blizzards,  of  Antarctica,  268. 

Foehn  winds,  234,  268,  270;  drying 
effect  of,  270 ;  local  intensification  of, 
in  Antarctica,  270 ;  of  Antarctica, 
271 ;  of  Bavarian  Highlands,  271 ;  on 
borders  of  Greenland,  149. 

Foetal  Glacier  outlets,  view  of,  226. 

Former  extent  of  Antarctic  glacier, 
279. 

Form  of  tongue-like  basin,  diagram, 
88. 

Foster  glacier,  Alaska,  45,  pi.  10. 

Franz  Josef  Land,  106 ;    map  of,  107. 

Fretted  upland,  29,  pis.  4,  6,  7 ;  com- 
pared with  etched  faces  on  crystals, 
40 ;  in  part  submerged,  pi.  17 ;  East 
Greenland,  pi.  22. 

Fricker,  Karl,  cited,  210,  212. 

Friederickshaab  glacier,  Greenland,  44 ; 
map  of,  171. 

Friedrichsen,  Max,  cited,  57. 

Fringing  glaciers,  274,  pi.  27 ;  Green- 
land, 151. 

Fringing  ice-foot,  209. 

Front  of  Greenland  glacier,  127-128. 

"Frost  snow,"  Greenland,  144,  145,  153; 
Antarctica,  263. 

Future  condition  of  Antarctica,  possible 
effect  upon  wind  system,  281. 

Gains  and  losses  of  glaciers,  how  con- 
trolled, 36. 

Gannett,  Henry,  cited,  15,  23,  242. 

Garde,  J.  V.,  cited,  120,  121,  129,  130, 
140,  141,  255. 

Garde's  route,  map  of,  in  southern  Green- 
land, 121. 

Garwood,  E.  J.,  cited,  23,  48,  57,  96. 

Gastaldi,  B.,  cited,  13,  22. 

"Gauss"  expedition,  189,  198,  203,  228. 

Gaussberg,  247,  248,  270,  280,  pis.  32, 
33. 

Gehangegletscher,  209. 

Geikie,  A.,  cited,  13,  15,  23. 

"Gendarmes,1'  30. 

Gerlache,  Adrian  de,  cited,  191,  211, 
213. 

Gilbert,  G.  K.,  cited,  11,  18,  23,  26,  28, 
39,  52,  58. 

Glacial  abrasion,  9. 


Glacial  amphitheatre.     See  Cirque. 

Glacial  anticyclone,  essentials  of,  148 ; 
Antarctic,  265,  266. 

Glacial  cycle,  of  Davis,  6. 

Glacial  features  due  to  deposition,  81. 

Glacial  sculpture,  pi.  15  ;  by  Norwegian 
glaciers,  pi.  34;  high  latitude,  70; 
high  level,  25 ;  in  moderate  latitudes, 
low  level,  59. 

Glacial  theories,  ancestry  of,  1. 

Glacial  trough,  overdeepened  by  over- 
flow glacier,  view,  77. 

Glaciated  surface,  pi.  16 ;  furrowed  by 
shallow  channels,  map  showing,  73. 

Glaciated  valleys,  too  large  for  present 
streams,  67. 

Glaciation,  cycle  of,  6. 

Glacier  channels,  directed  by  rock 
structures,  75. 

"Glacier  docks,"  116. 

Glacierets,  hanging,  50,  53. 

"Glacier  run,"  105. 

Glaciers,  Arctic  type,  97 ;  classification 
of,  7,  41,  97,  285;  dependent  upon 
alimentation,  41 ;  first  appear  on  lee 
side  of  ranges  due  to  wind  distribu- 
tion, 28;  ice-foot,  209;  in  Caucasus 
Mountains,  38 ;  initial  forms  of,  37 ; 
life  history  of,  36  ;  mountain,  nourish- 
ment of  in  polar  regions,  260 ;  moun- 
tain, types  of,  pi.  11;  "new-born," 
37  ;  nivation,  37  ;  nourishing  processes 
8 ;  outlet,  104 ;  rock,  of  Alaska,  96 ; 
size  of,  in  relation  to  land  masses,  101 ; 
slope,  209 ;  Spitzbergen  type,  210. 

Glacier  stars,  166,  168. 

Glacier  Tongue,  231. 

Gletscher sterne,  166,  168. 

Glint  lakes,  136. 

Gorge  of  the  Albula  River,  view  of, 
90. 

Gorges  in  glaciated  valleys,  how  formed, 
66. 

Corner  glacier,  52. 

Gourdon,  E.,  cited,  5,  158,  161,  200,  206, 
209,  212,  213,  237,  243,  244,  251,  252, 
272,  281,  282,  283,  284. 

Gradation,  from  nivation  to  glaciation, 
20. 

Graham  Land,  211. 

Grat,  32. 

Great  Aletsch  glacier,  50,  52,  pis.  5,  12 ; 
size  compared  to  Beardmore  outlet, 
258. 

Great  Karajak  glacier,  178. 

Great  Ross  Barrier.     See  Ross  Barrier. 

Greely,  A.  W.,  cited,  116,  118,  210. 

Greenhalgh  Mountain,  rock  streams  on, 
pi.  19. 

Greenland,  map  of,  120. 


INDEX 


295 


Greenland  glacier,  air  circulation  over, 
146 ;  asymmetry  of,  162 ;  east  and 
west  shores  compared,  162 ;  nourish- 
ment of,  143;  outlines  of,  119. 

Gregory,  John  W.,  cited,  111. 

Grinnell  Land,  map  of,  115. 

Grooved  upland,  29,  pis.  4,  6. 

Grossmann,  Karl,  cited,  7,  11. 

Hanging  glacier,  defined,  57. 

Hanging  glacierets,  50,  54,  pis.  12,  14. 

Hanging  valley,  48,  61,  66,  67,  pi.  13. 

Hardangerjokull,  102,  pi.  17. 

Harker,  Alfred,  cited,  40. 

Hauthal,  R.,  cited,  177. 

Hayes,  C.  W.,  cited,  57. 

Hayes,  I.  I.,  cited,  121. 

Head-wall  erosion,  10. 

Heat  transfer,  between  poles  and  equa- 
tor, 99. 

Holland,  Amund,  cited,  13,  14,  22.  141. 

Hemicycle,  advancing,  35  ;   receding,  89. 

Hemicycles  of  glaciation,  6. 

Hess,  H.,  cited,  7,  40,  56,  118,  122,  137, 
141,  238,  240,  244. 

High  latitude  glacial  sculpture,  70. 

High  level  clouds,  bring  snow  to  interior 
of  Antarctica,  274. 

High  level  glacial  sculpture,  8. 

Hispar  glacier,  47,  50. 

Hobbs,  W.  H.,  cited,  24,  96,  117,  210, 
260. 

Hofer,  Hanns,  cited,  118. 

Hofs  Jokull,  102,  103. 

Hollander,  L.  M.,  cited,  78. 

Holmes,  W.  H.,  cited,  81. 

Horn,  defined,  33. 

Horns,  in  relation  to  neves,  33. 

Horseshoe  Glacier,  the,  in  the  Canadian 
Rockies,  54. 

Horseshoe  glaciers,  53 ;  concavity  of 
frontal  margin,  54 ;  of  Antarctica, 
259. 

Howe,  Ernest,  cited,  95,  96. 

Hugi,  F.  G.,  cited,  3. 

Humidity  of  air,  absolute,  in  Greenland, 
145-146;  in  Antarctica,  262;  rela- 
tive, in  Greenland,  145,  146. 

Hummocks,  in  sea-ice,  204. 

Huntington,  Ellsworth,  cited,  10. 

Hydraulic  ram  effect,  at  termination  of 
Antarctic  blizzard,  270. 

Hyperbolic  form,  of  col,  34. 

Ice  aprons,  below  outlets,  257. 

Ice  barrier,  surface  of,  pi.  30. 

Iceberg,  in  Melville  Bay,  view  of,  182. 

Icebergs,  Antarctic,  beauty  of,  240,  241  ; 
Antarctic,  debris  in,  241 ;  Antarctic, 
drift  of,  240;  Antarctic,  melting  of, 


241 ;  Arctic,  manner  of  birth  of,  178 ; 
blue,  of  Antarctica,  239,  248;  of 
Antarctica,  in  parallel  ranges,  203 ; 
of  Greenland,  182,  183  ;  of  ice-dammed 
lakes,  179;  the  anchorage  of  "West 
ice,"  250;  rock  debris  in,  249;  von 
Drygalski's  classification  of,  249  ; 
tabular,  deformation  of,  239  ;  tabular, 
embryonic  forms  of,  251 ;  tabular, 
Antarctica,  234 ;  tabular,  forming 
from  Ross  Barrier,  view  of,  235 ; 
tabular,  rectangular  plan  of,  237 ; 
tabular,  stratification  of,  239 ;  tabu- 
lar, views  of,  236,  237. 

Ice  blink,  defined,  141. 

Ice-cap,  of  Eyriksjokull,  7 ;  suddenly 
melted  by  lava,  105 ;  transitional 
position  of,  7. 

Ice-cap  glaciers,  42  ;  of  East  Greenland, 
124. 

Ice-caps,  of  Iceland,  8,  102 ;  of  Norway, 
8,  104  ;  on  volcanic  peaks,  8. 

Ice-caves,  208. 

Ice-cliff,  at  fjord  heads,  Greenland,  178. 

Ice-cones,  debris  covered,  168. 

Ice  crystals,  in  glacial  anticyclone,  270. 

Ice-dammed  lakes,  pis.  25,  26 ;  in  Green 
Mountains,  172. 

Ice  dams,  in  extraglacial  drainage,  174. 

Ice  face,  of  Greenland  glacier,  127,  pi.  23. 

Ice  flowers  (rosette-like  ice  crystals),  199. 

Ice-foot,  208. 

Ice-foot  glaciers,  208,  209,  pi.  27. 

Ice  front,  of  Greenland  glacier,  pi.  24. 

Ice  grains  in  water,  precipitated  in 
sunlight,  277. 

Ice  grottoes,  about  nunataks,  169. 

Ice  island,  208,  pi.  28 ;  views  of,  209,  pi. 
28. 

Ice  plateau,  of  Antarctica,  monotony  of, 
256. 

Ice  slabs,  259,  280. 

Ice-tongues  (outlet  glaciers),  125-126. 

"Icy  barrier,"  how  used  by  Wilkes,  215. 

Ideal  cross-section,  of  U-valley  and  Albs, 
64.  , 

Illecillewaet  glacier,  50. 

Inherited  basin  glacier,  50. 

Initiation  of  glaciation,  5. 

Inland  Forts,  Victoria  Land,  259. 

Inland-ice,  contrasted  with  mountain 
glaciers,  285 ;  ideal  section  across,  7  ; 
in  relation  to  basement,  7 ;  physio- 
graphic form  of,  7  ;  of  Kaiser  Wilhelm 
Land,  pi.  32  ;  of  Spitz bergen,  views  of, 
111-112. 

Insolation,  over  Antarctic  glacier,  262, 
263. 

International  cooperative  expeditions  to 
Greenland,  desirable,  143. 


296 


INDEX 


Intersecting     crevasses     in      Antarctic 

glaciers,  map  of,  247. 
Isblink,  defined,  141. 
Ivory  Gate,  the,  on  Spitz bergen,  111. 

Jackson,  F.  G.,  cited,  118. 

Jamieson,  T.  F.,  cited,  172,  177. 

Jensen,  J.  A.  D.,  cited,  120,  140,  170, 
171,  176. 

Johnson,  Willard  D.,  cited,  15,  17,  18,  23, 
25,  39,  68;  his  exploration  of  a 
Bergschrund,  16. 

Joint  planes,  in  connection  with  land- 
slides, 92. 

Jokulhlaup,  105. 

Jostedalsbraen,  pi.  18 ;  map  of,  pi.  20. 

Jotenheim,  pi.  34. 

Kaiser  Wilhelm  Land,  193,  195,  203,  216, 
239,  244,  246,  250,  253,  263,  265,  272, 
280,  pi.  32. 

Kames,  in  Greenland,  140. 

Karajak  glaciers,  sections  of,  179. 

Karling,  defined,  32;  in  North  Wales, 
pi.  8. 

Karso  trough  valley,  in  Northern  Lap- 
land, view  of,  71. 

Kemp,  cited,  192,  197. 

Kemp  Land,  192,  195,  215. 

Kennicott  glacier,  48. 

Kilimandjaro,  ice-cap  of,  43. 

King  Edward  Land,  193,  195,  209,  216. 

King  Oscar  Land,  211,  216;  ice  terraces 
of,  224  ;  map  of  ice  terraces,  225. 

Klutlan  glacier,  Alaska,  46. 

Knobs  rising  from  dome  as  result  of 
ice-cap  glaciation,  view  of,  76. 

Kornerup,  cited,  171. 

Krech,  cited,  209. 

Lake  Argentine,  174,  pi.  25. 

Lake  Constance,  origin  of,  83,  84. 

Lake  Garda,  formation  of,  84. 

Lake  ice,  manner  of  formation  of,  226. 

Lake  Mono  glaciers,  former,  pi.  15. 

Lake  Tyndall,  174. 

Lakes,  border,  83 ;  in  drift  ice,  lozenge- 
shaped,  203;  marginal,  to  Greenland 
glacier,  171-173  ;  morainal,  82. 

Landslide,  of  Elm  in  Canton  Glarus,  93  ; 
of  Frank,  Alberta,  92. 

Landslides,  in  Colorado,  92 ;  in  valley 
vacated  by  glaciers,  91. 

Lang  Jokull,  102,  103. 

Lapland,  former  glaciers  of,  39. 

Lapp's  Gate,  Lapland,  73. 

Larsen  Bay,  sea-ice  of,  225. 

Latent  heat  transformations,  during 
Antarctic  blizzard,  269. 

Lateral  moraines,  Victoria  Land,  259. 


Lateral  streams,  of  outlet  glaciers,  169. 
Laurentian  district  of   North  America, 

temperature  necessary  for  glaciation, 

5. 

Law  of  adjusted  cross-sections,  60,   137. 
Lawson,  A.  C.,  cited.  25,  26,  30,  39,  57. 
Leads,  200,  206. 
Lefroy  glacier,  Selkirks,  50. 
Lendenfeld,  R.  v.,  cited,  57. 
Leslie,  A.,  cited  (translator),  277,  283. 
Leverett,  Frank,  cited,  10. 
Life  history  of  a  glacier  (Russell),  6. 
Little    Cottonwood     canyon,     U-valley, 

pi.  16. 

Lockwood,  Lieutenant,  cited,  128. 
Lofoten  Islands.  Norway,  31,  pi.  7. 
Low  level  glacial  sculpture,  8,  59. 
Lozenge-shaped  lakes,  in  drift  ice,  202. 

Machacek,  Fritz,  cited,  80,  pi.  34. 

McMurdo  Sound,  218,  231,  253,  259,  264, 
267,  276,  279. 

Maine,  gulf  of,  probable  former  shelf- 
ice  in,  214. 

Malaspina  glacier,  43  ;  evolution  of,  37. 

Map,  Antarctica,  194,  195 ;  Asulkan 
glacier,  54  ;  Baird  glacier,  46  ;  Beard- 
more  outlet,  258 ;  David's  route  to 
south  magnetic  pole,  267  ;  Greenland, 
showing  inland-ice,  120;  Hispar  gla- 
cier, 47 ;  Hofsjokull  and  Langjokull, 
102;  Illecillewaet  glacier,  49;  King 
Oscars  and  Kaiser  Franz  Josef  fjords, 
124 ;  Lake  Garda,  84 ;  North  Green- 
land, 133  ;  of  area  near  Tornetrask, 
Swedish  Lapland,  72 ;  areas  of  heavy 
glaciation,  northern  hemisphere,  100 ; 
braided  stream,  from  Iceland,  86 ; 
fixed  "lows"  in  northern  hemisphere, 
100 ;  glaciated  and  unglaciated  rock 
near  McMurdo  Sound,  279 ;  Great 
Ross  Barrier,  217 ;  morainic  ridges  in 
front  of  Wasatch  Range,  82 ;  Ross 
Barrier  (outline),  220;  margin  of 
Ross  Barrier,  2 17-;  Northeast  Fore- 
land, Greenland,  127  ;  shelf-ice  tongues 
of  Ross  Sea,  232;  soundings,  "Bel- 
gica,"  196 ;  radiating  glacier  of  the 
Nicolai  valley,  53 ;  shelf-ice  tongues, 
Robertson  Bay,  230;  Sheridan  gla- 
cier, 45  ;  Storfjord  with  joint  directed 
valleys,  75 ;  terraces  of  King  Oscar 
Land,  225 ;  showing  dimple  above 
Ferrar  glacier,  Antarctica,  256  ;  show- 
ing superglacial  streams  on  Greenland 
glacier,  165 ;  Tasman  glacier,  48  ; 
Victoria  and  Lefroy  glaciers,  50; 
Wenkchemna  glacier,  55. 

Marginal  contours,  of  contrasted  glacier 
types,  289. 


INDEX 


297 


Marginal  cross-sections,  Antarctic  gla- 
cier, 253. 

Marginal  lakes,  Greenland  glacier,  171- 
173. 

Marginal  moraines,  Greenland,  138,  139. 

Marginal  physiography,  of  Greenland 
glacier,  123. 

Marguerite  Bay,  field  ice  of,  251. 

Miirjelensee,  175. 

Markham,  Sir  Clements,  cited,  210. 

Martin,  G.  C.,  cited,  45,  46,  56,  57. 

Martin,  Lawrence,  cited,  46,  57. 

Martonne,  E.  de,  cited,  13,  23,  61,  62,  63, 
64,  65,  66,  67,  68,  69. 

Matterhorn,  33,  pi.  9. 

Matthes,  Francois  E.,  cited,  15,  19,  20, 
22,  23,  26,  39,  40,  57. 

Mawson,  Douglas,  cited,  207,  212,  213, 
282. 

Mawson  outlet,  234. 

Medial  moraines,  Greenland,  138 ;  Vic- 
toria Land,  259. 

Melting  of  Antarctic  ice,  234. 

Melting  of  Greenland  glacier  toward 
interior,  146. 

Melville  Bay,  178  ;  ice  margin  at,  132. 

Mendenhall  glacier,  Alaska,  45. 

Mendenhall,  W.  C.,  cited,  57. 

Mer  de  glace,  52,  53. 

Merwin,  H.  E.,  cited,  177. 

Meyer,  Hans,  cited,  56,  57. 

Miles  glacier,  Alaska,  45. 

Mill,  H.  R.,  cited,  210,  212. 

Mills  (Moulins)  on  Greenland  glacier, 
166. 

Minna  Bluff,  222,  pi.  30. 

Moat,  Antarctic,  view  of,  pi.  33. 

Moats,  Antarctic,  257 ;  Greenlandic, 
169. 

Mohri,  H.,  cited,  140,  142,  160,  176. 

Mont  Blanc,  significance  of  its  dome 
form,  32. 

Moraines,  ground,  81 ;  lateral,  Belgica 
Strait,  281 ;  lateral,  Victoria  Land, 
259;  marginal,  138,  139;  medial,  81, 
138;  medial,  Victoria  Land,  259; 
of  mountain  glaciers,  81  ;  on  flanks 
of  Sawatch  Range,  view  of,  81 ;  re- 
cessional, 82,  87;  terminal,  about 
apron  sites,  83,  84 ;  terminal,  of 
Greenland  glacier,  pi.  24. 

Moreno,  Francisco  P.,  cited,  177. 

Mossman,  R.  C.,  cited,  210. 

Mt.  Assiniboine,  33. 

Mt.  Lyell  glacier,  55. 

Mt.  Ranier,  pi.  13. 

Mt.  Sir  Donald,  pi.  9. 

Mountain  foreland,  apron  sites  on,  83, 
84  ;  stream  action  of,  85. 

Mountain  glacier,  ideal  section  across,  7. 


Mountain  glaciers,  alimentation  of,  36; 
cauldron  type,  51 ;  contrasted  with 
inland  ice,  285;  "dead,"  51 ;  defined, 
6 ;  dendritic  type,  47  ;  evolution  of  r 
37 ;  form  sensitive  to  temperature 
changes,  41 ;  horseshoe  type,  53 ; 
inherited-basin  type,  50 ;  in  relation, 
to  basement,  7;  "living,"  51;  mar- 
ginal to  Greenland,  view  of,  122 ; 
nivation  type,  42 ;  nourishment  of,  in- 
polar  regions,  260 ;  of  Antarctica,  259 ; 
on  volcanic  cone,  pi.  13 ;  on  volcanie 
peaks  in  low  latitudes,  51 ;  piedmont 
type,  43  ;  radiating  (Alpine)  type,  52  ; 
relation  to  bed,  41 ;  tide-water  sub- 
type, 51 ;  transection  type,  44  ;  types 
of,  42,  pi.  11. 

Mountain  rampart,  of  Victoria  Land, 
253  ;  of  Antarctica,  mountain  glaciers 
on,  259. 

Movement,  of  Antarctic  glacier,  248  ; 
of  Antarctic  glacier,  in  Kaiser  Wil- 
helm  Land,  222 ;  of  Pleistocene  gla- 
cier in  Scandinavia,  136 ;  rate  of,  in 
glacier  outlets,  134. 

Multiple  cirques,  pi.  5. 

Murray,  George,  cited,  210. 

Murray,  Sir  John,  cited,  212,  241,  242, 
244,  265. 

Nansen,  Fritjof,  cited,  4,  120,  122,  123, 

124,  129,  131,  132,  138,  140,  141,  142, 

144,  145,  148,  150,  160,  161,  162,  176, 

207,  255,  263. 

Nathorst,  A.  G.,  cited,  141. 
Neu-Haufen  dyke,  Danube,  map  of,  136. 
Neumayr,  Georg  v.,  cited,  210. 
Neve  snow  of  Greenland,  153. 
Nivation,  18 ;    in  Yellowstone  National 

Park,   view  of,   pi.   2 ;    on   Quadrant 

Mountain,  Yellowstone  National  Park, 

20 ;  in  Swedish  Lapland,  20. 
Nivation  glaciers,  37,  42. 
"Noah's  Ark"  clouds,  275. 
Nordenskiold,  A.  E.,  cited,  4,  113-118, 

122,  123,  144,  150,  160,  161,  166,  169, 

170,  176,  255,  276,  277,  283. 
Nordenskiold,  Gustav,  cited,  112. 
Nordenskiold,  Otto,  cited,  24,  96,   189, 

191,  209,  210,  211,  213,  224,  225,  243, 

252,  270,  281,  283,  284. 
Nordenskiold  shelf-ice  tongue,  231,  234, 

251,  280. 

Northeast  Foreland,  Greenland,  178. 
North  East  Land,  inland-ice  of,  112-113  ; 

map  of,   110;    peculiar  precipitations 

over,  276. 
Northern  Lapland,  surface  features  of, 

71. 
North  Wales,  32. 


298 


INDEX 


Norway,  cirques  of,  13. 
Norwegian  ice-caps,  101. 
Norwegian  tind,  formation  of,  78. 
Nourishment  of  Greenland  glacier,  131, 

143. 

Nova  Zembla,  110  ;  map  of,  109. 
Nunataks,  73 ;    in  surface  of  Folgefond, 

view  of,  76  ;   of  Greenland,  125. 
Nussbaum,  cited,  68,  69. 

Ocean  currents,  in  relation  to  glaciers,  99. 

Olriks  Bay,  Greenland,  kames  of,  140. 

Osar,  formation  of,  89. 

Outlet  glacier,  denned,  221. 

Outlet    glaciers,    104;     dead,    253;     of 

Greenland,   126 ;    Greenland,  map  of, 

125. 

Outlets,  from  Antarctic  glaciers,  221. 
Outwash  apron,  87. 

Overdeepening,  in  glaciated  valleys,  66. 
Overthrusting,  on  margins  of  Greenland 

ice,  140,  pi.  23. 

Pack-ice,  Antarctica,  198,  200,  203. 

Palander,  cited,  4. 

Palisade  ridge  (comb-ridge),  32. 

Palmer  Land,  211. 

Pancake  ice,  208. 

Parallel  crevasses,  in  Greenland  glacier, 
view  of,  129. 

"Parallel  roads,"  of  Scottish  Glens,  172. 

Passarge,  S.,  cited,  10. 

"Paternoster"  Lakes,  60. 

Peary,  Robert  E.,  cited,  4,  120,  123,  126, 
129,  130,  131,  132,  133,  134,  141,  145, 
146,  150,  153,  154,  155,  160,  164,  166, 
169,  170,  176,  207,  209,  252,  255,  266, 
276. 

Penck,  Albrecht,  cited,  10,  11,  13,  18,  23, 
40,  56,  60,  61,  69,  83,  84,  88,  96,  137, 
212. 

Philippi,  Emil,  cited,  198,  212,  227,  241, 
243,  252. 

Physiographic  form  of  glaciers,  285. 

Physiography  of  Greenland  continental 
glacier,  119. 

"Pie  crust"  snow,  surface,  263. 

Piedmont  aprons,  dead,  280. 

Piedmont  glaciers,  43,  pi.  10. 

"Piedmont"  (ice-foot)  glaciers,  209. 

"Piedmonts  afloat,"  231. 

Pillsbury,  Admiral  John  E.,  cited,  212. 

"Planks,"  in  sea-ice,  204. 

Playfair,  Sir  John,  cited,  67. 

Pleistocene  glaciation,  characteristic  ero- 
sion from,  72. 

Plucking,  9. 

Polar  regions,  contrasted,  186. 

Posadowsky  Bay,  203,  241. 

Poudrin,  273. 


Precipitous  rock  face,  characteristic  of 

sculpture  by  mountain  glaciers,  91. 
Pressure,  in  pack-ice,  200. 
Pressure  ridges,  in  sea-ice,  204 ;    views 

of,  204-205. 

Priestley,  R.  E.,  242,  243. 
Prince  Rudolph  Island,  ice-cap,  106,  107  ; 

view  of,  108. 
Profiles,     of    sub-aerial    and    glaciated 

valleys,  68. 

"Protection"  by  glaciers,  28,  66. 
Purity  Range,  of  Selkirks,  Frontispiece. 

Quadrant  Mountain,  Yellowstone  Na- 
tional Park,  views  of,  pis.  2,  3 ;  map 
of,  27  ;  nivation  upon,  20. 

Quensel,  P.  D.,  cited,  177. 

Rabot,  cited,  56. 

Racovitza,  E.,  cited,  199,  211,  212,  262, 

282,  283. 

Radiating  glaciers,  52. 
Rainbow  with  halo,  277. 
Ramsey,  cited,  40. 
Randsee,  174. 
Rate   of   movement,    Greenland   glacier 

outlets,  134. 
Receding  hemicycle  of  glaciation,  6,  89, 

280;    Greenland,  143-144. 
Receding  of  Ross  Barrier,  227. 
Recessional  moraines,  87. 
Recession,  of  cirque,  12. 
Reconstructed  glaciers,  50. 
Rectangular  crevasses  in  ice  of  Kaiser 

Wilhelm  Land,  130. 
Refrigerating  air  engine,  over  continental 

glacier,  269,  286. 
Reid,  H.  F.,  cited,  180,  181,  185,  238, 

243. 

Reid's  theory  of  iceberg  formation,  181. 
Relation  of  cirque  to  Bergschrund,  14. 
Remnantal   tableland,  figure   after    At- 

wood,  27. 

Retirement  of  glacier,  up  valley,  89. 
Reusch,  H.,  cited,  15,  23. 
Rhone  glacier,  91. 
Ribbon  falls,  48. 

Richter,  E.,  cited,  13,  14,  15,  17,  23. 
Richtofeneis,  of  Kerguelen  Island,  43. 
Riegel,  63,  90. 
Rimaye.     See  Bergschrund. 
Rink,  Henry,  cited,  149,  160,  175,  177. 
Robertson  Bay,  230,  231. 
Roches   moutonnees,  39,  64 ;    of  Antarc- 
tica, 281. 
Rock  bars,  63,  90. 
Rock     basement,     beneath     Greenland 

glacier,  125. 
Rock  basin  lakes,  60. 
Rock  flows,  from  abandoned  cirques,  94. 


INDEX 


299 


Rock  glaciers,  94 ;   of  Alaska,  96. 

Rock  pedestals  (enclosed  by  fjords),  75. 

Rock  slides,  near  Flims,  view  of,  93. 

Rock  streams,  in  vacated  valley,  91,  pi. 
19 ;  in  San  Juan  Mountains,  map  of, 
95. 

Rocky  Mountains,  foehn  winds  of,  271. 

Ross  Barrier,  193,  196,  216;  evidence 
for  floating  of,  221 ;  face  of,  pis.  29, 
31 ;  inner  margins  of,  221 ;  map  of 
margin  of,  217 ;  margins,  views  of, 
219;  material  of,  218;  movement  of, 
222,  224;  nourishment  of,  221,  272; 
old  and  new  faces  on,  235 ;  outline 
map  of,  220  ;  recession  of,  227  ;  surface 
of,  220. 

Ross,  Sir  James,  cited,  190,  193,  198, 
215,  216,  218,  238,  262,  264,  265. 

Royds,  C.  W.,  cited,  220,  282,  283. 

Bundling,  39. 

Russell's  theory  of  iceberg  formation, 
180. 

Russell,  I.  C.,  cited,  6,  11,  13,  23,  43,  56, 
57,  58,  59,  68,  88,  96,  180,  184,  185. 

Russian  Lapland,  glaciation  of,  72. 

Ryder,  C.  H.,  141,  161,  170,  176. 

Sago  snow,  262. 

"Sahara  of  snow,"  view  of,  151. 

Salisbury,  R.  D.,  cited,  12,  22,  60,  118, 
142,  153,  160,  170,  185. 

Sand  dune,  marginal  view  of,  273. 

San  Juan  Mountains,  rock  flows  in,  94. 

San  Rafael  glacier,  Chili,  44. 

Sapper,  Carl,  cited,  118. 

Sapping  process,  in  cirque  recession,  91. 

Sastrugi,  154,  158 ;  Antarctica,  203,  267, 
268,  273;  on  schollen  ice,  view  of, 
204 ;  on  shelf -ice,  pi.  30. 

Saussure,  H.  B.  de,  cited,  2. 

Scape  colks,  135,  140. 

Scattered  knobs,  a  result  of  high  latitude 
glaciation,  72. 

Scheuchzer,  cited,  3. 

Schollen  ice,  200,  203. 

Schrader,  F.  C.,  cited,  57. 

Schrund-line,  18 ;  continued  down  valley, 
64 ;  view  of,  after  Gilbert,  18. 

Scoresby,  cited,  213. 

Scott,  R.  F.,  cited,  189,  190,  191,  193, 
200,  209,  210,  211,  212,  213,  216,  218, 
220,  242,  243,  244,  254,  255,  257,  260, 
266,  267,  276,  280,  282,  284. 

Scottish  highlands,  temperature  neces- 
sary for  glaciation,  5. 

Sea-ice,  Antarctica,  186,  198;  forma- 
tion of,  199,  206,  207;  manner  of 
growth  of,  208;  thickening  of,  226, 
250 ;  thickness  of,  199,  200. 

Seal  Islands,  224. 


Section,  across  Vatna  Jokull,  274;  of 
ice  grains  in  water,  precipitated  in 
North  East  Land,  277  ;  of  Great  Ross 
Barrier,  217;  marginal  portion  of  ice- 
cap, 101. 

Sections,  across  Antarctic  glacier  margin, 
253,  254 ;  across  margins  of  Green- 
land glacier,  123  ;  comparative,  across 
Greenlandic  and  Antarctic  continental 
glaciers,  255. 

Selkirks,  30. 

Seter,  172. 

Seven  Sisters,  view  of,  77. 

Shackleton,  Sir  Ernest,  cited,  147,  189, 
191,  193,  200,  210,  211,  220,  232,  242, 
243,  254,  256,  258,  266,  272,  274,  276, 
282,  283,  284. 

Shaping  of  Antarctic  glacier  margins,  by 
wind,  273. 

Shelf-ice,  214 ;  alimentation  of,  221,  226, 
227;  density  of,  218;  how  formed, 
288 ;  nature  and  distribution  of,  214. 

Shelf-ice  tongue,  supposed  section  of, 
233. 

Shelf-ice  tongues,  230,  231. 

Sheridan  glacier,  in  Alaska,  45. 

Sherzer,  W.  H.,  cited,  55,  57,  58. 

Sierra  Nevadas,  California,  glacial  sculp- 
ture in,  pi.  15. 

Sinking  of  "Antarctica,"  205. 

Sir  John  Murray  glacier,  230,  231,  233. 

Sjogren,  O.,  cited,  71,  73. 

Sketch  map  of  north  border  of  Alpine 
Highland,  85. 

Skottsberg,  C.  J.,  cited,  213. 

Sky,  in  interior  of  Greenland,  144 ; 
nature  of,  during  snowfall,  262. 

Slabs,  ice,  259. 

Sledge  journeys,  of  Peary  in  north  Green- 
land, map,  133. 

Slope  glaciers,  209. 

Snow,  Antarctic,  in  summer  season,  5 ; 
blown  off  Antarctica  into  sea,  280 ; 
compressed,  in  Ross  Barrier,  218  ;  den- 
sity of,  157 ;  drifting,  over  Greenland 
glacier,  151;  "pie  crust,"  263;  pre- 
cipitated through  mixing  of  surface 
air  with  descending  currents,  277 ; 
smooth-sledging  type,  263  ;  structure 
of,  on  surface  of  Greenland  glacier, 
153 ;  transported  by  wind,  271. 

Snow  barchans,  156. 

Snowdrift  forms,  154. 

Snowdrift  site,  figured  after  Matthes,  19. 

Snow  dunes,  on  margin  of  Greenland 
glacier,  132. 

Snowfall,  character  of,  what  dependent 
upon,  155 ;  Greenlandic,  source  of  in 
cirrus  clouds,  158  ;  in  Antarctica,  223  ; 
in  Greenland,  144 ;  in  interior  of  Ant- 


300 


INDEX 


arctica,  264 ;    of  Antarctica,    in  sum- 
mer months,  226 ;  nature  of,  in  Ant- 
arctica, 262. 
Snowflakes,    nature    of    in    relation    to 

temperature  of  precipitation,  262. 
Snow  Hill  Island,  189,  226,  270. 
Snow-line,  defined,  5. 
Snow  precipitation,  at  end  of  blizzard, 

279. 
Snow  sweepings,  from  Antarctic  glacier, 

251. 

Sobral,  J.  M.,  cited,  224. 
Solifluction,  process  of,  21,  94. 
Soundings,  about  Antarctica,   196,   197, 

198,   218,   245;    Antarctica,   map   of, 

196. 

Spethmann,  Hans,  cited,  104,  118,  274. 
Spitzbergen,   expedition  to  in   1858,   4 ; 

inland-ice  of,  111;    map  of,  110. 
Spitzbergen  type  of  glacier,  210. 
Staircase,   due  to  successive  landslides, 

92. 

Steffen,  Hans,  cited,  177. 
Stein,  Robert,  cited,  160,  161,  170,  176. 
Steps,  in  glaciated  valley,  61. 
Stille,  H.,  cited,  243. 
Stone  rivers,  94. 
Stratification,  in  ice  island,  pi.  28 ;    of 

continental  glacier,  248,  pi.  22. 
Stream   action,   in   valley  while   glacier 

retires,    89 ;     on    mountain    foreland, 

85. 
Streams,  braided,  86 ;    lateral,  of  outlet 

glaciers,  169. 
Sturge  Island,  209. 
Subglacial  drainage,  on  Greenland,  glacier, 

170. 

Subglacial  streams,  Antarctica,  234. 
Submarine  wells,  in  fjord  heads,  175. 
Submerged  continental  platform,  about 

Antarctica,  196. 

Suess,  E.,  cited,  135,  136,  142,  172,  176. 
Supposed  south  polar  anticyclone,  265. 
Superglacial  debris,  on  Antarctic  glaciers, 

259. 
Superglacial     streams,     on     Greenland 

glacier,  map  of,  165. 
Surface  moraines,  Greenland,  135 ;   cross 

section  of,  139 ;    view  of,  139. 
Sverdrup  expedition,  117. 
Sverdrup,  Otto,  cited,  118. 
Swedish  polar  expedition  of  1872-1873, 

4. 
Swirl  colks  (ice  eddies),  137. 

Tabular  icebergs,  views  of,  236,  237. 

"  Tapioca  "  snow,  262. 

Tarr,  R.  S.,  cited,  46,  48,  56,  57,  58,  88, 

105,  128,  138,  141,  142,  162,  173,  176, 

177,  185. 


Temperature,  its  relation  to  glaciation, 

36. 
Temperatures,   air,   Antarctic,    188-189, 

262;    in  relation  to   glaciation,   278; 

over    inland-ice    of    Greenland,    145  ; 

serial  subsurface,  in  Greenland  glacier, 

163  ;  serial  subsurface,  in  Ross  Barrier, 

221. 
Terraced  margin,  of  Greenland  glacier, 

130. 
"Terraces,"  of  King  Oscar  Land,  224; 

West  Antarctica,  origin  of,  250. 
Thomson,  Wyville,  cited,  236,  238,  240, 

243,  264. 
Thoroddsen,    Th.,    cited,    56,    102,    103, 

104,  118,  274,  284. 
Tide-cracks,  208. 
Tide-water  glaciers,  51. 
Tinds,  development  of,  78,  79,  286 ;  pis. 

18,  34;   remarkable  circular  one  from 

Lofoten  Islands,  view  of,  78. 
Tongue-like  basin,  before  mountain  front, 

83,  88. 

Torell,  Otto,  cited,  4. 
Transection  glacier,  former  over  Grimsel 

pass,  45. 

Transection  glaciers,  44. 
Transportation  of  snow,  by  wind,  271. 
Tresca,  cited,  201. 
Triest  glacier,  pi.  12. 
Trogthal,  62. 
Trolle,  Lieutenant  A.,  cited,  127, 141, 160, 

163,  176. 

Tschirwinsky,  P.  N.,  cited,  161. 
Tuktoo  glacier,  pi.  23. 
Turner  glacier,  Alaska,  52. 
Turtle  Mountain,  landslide  from,  92. 
Tyndall,  John,  cited,  12,  22,  91,  96. 
Tyrrell,  J.'B.,  cited  236,  243. 

Uinta  Mountains,  cirque  cutting  in,  26. 

Umanak  Fjord  glacier  outlet,  Greenland, 
125. 

Upland,  dissected  by  glaciers,  25. 

Uplifts  in  connection  with  glacial  sculp- 
ture, 74. 

Upper  air  currents,  function  in  nourish- 
ing Antarctic  glaciers,  269. 

Urville,  J.  S.  C.  Dumond  de,  cited,  190, 
193,  210. 

U-valleys,  63;  initiation  of,  20;  over- 
emphasis upon,  8 ;  Wasatch  Range, 
pi.  16. 

"Valley"  glaciers,  47. 

Vatna  Jokull,  43,  103,  274 ;  air  circula- 
tion over,  278  ;  cross  section  of,  104  ; 
map  of,  103 ;  map  of  margin  of,  pi. 
21. 

Venetz,  cited,  3. 


INDEX 


301 


Vernagt  glacier,  91. 
Victoria  glacier,  50. 

Wallace,  A.  R.,  cited,  13,  23. 
Wandel  Island,  199,  200,  207. 
Warm  season,  effect  of,  on  Greenland 

glacier,  163. 
Wasatch  Range,  pi.  16. 
Water  basins,  on  Greenland  glacier,  166. 
Water  fountain,   on   Greenland  glacier, 

170. 

Water  sky,  in  ribbons,  cause  of,  202. 
Weddell,  James,  cited,  192. 
Weddell  Sea,  189,  193,  223,  244. 
Wenkchemna  glacier,  pi.  14. 
Werth,  Emil,  cited,  56. 
West  Antarctica,  192,  199,  209,  238,  251. 
"West-ice,"  junction  with  sea-ice,  view 

of,    228;     of    Kaiser   Wilhelm    Land, 

227;    origin  of,  250;    stranded,  229; 

surface  of,  229  ;  view  from  sea,  228. 
Wheeler,  A.  O.,  cited,  49,  50. 
White  Island,  189. 
Whymper,  Edward,  cited,  150. 
Widening  of  glacier  valleys  at  mouths, 

66. 


Wilkes,  Captain  Charles,  cited,  190,  192, 
193,  211,  212,  215,  238,  242,  243,  244, 
264. 

Wilkes  Land,  192,  193,  195,  240. 

Wilson,  E.  A.,  cited,  280. 

Wind  directions,  over  Antarctic  glacier, 
266,  267. 

Wind  poles,  281. 

Wind  transportation  of  snow,  over 
Greenland  ice,  150. 

Winds,  Antarctic,  sweep  inland-ice  clear 
of  snow,  247 ;  importance  of  in  dis- 
tribution of  snow,  28,  151,  271 ;  in 
relation  to  alimentation  of  Antarctic 
glacier,  226 ;  on  border  of  Greenland, 
149 ;  prevailing,  on  margins  of  Ant- 
arctica, 263,  264. 

Workman,  Fanny  Bullock,  cited,  57. 

Workman,  Wm.  Hunter,  cited,  57. 

Yoho  glacier,  pi.  3. 

Zigzag  leads,  in  drift  ice,  202. 
Zungenbecken,  83. 
Zusammengesetzte  Gletscher,  52. 


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